How Often Do You Replace Your Mower Blades?

Posted July 19, 2016 by 66 Comments

How often do you replace the blades on your mower?

Do you have a small lawn and survive an entire year with one set of blades? Or are you a commercial landscaper that is left with dull blades by the end of every week?

Regardless of how often you mow, your blades can easily become dented, worn, bent, and damaged either over time or as a result of hitting objects such as woodchips and rocks. You should regularly inspect your blades, as broken blades can quickly become dangerous projectiles and can also potentially damage your mower.

Before attempting to inspect or replace your blades, consult your owner’s manual for information regarding safety, warranty, and specifics about your model. Remember to always wear heavy protective gloves when working with blades.

How to Change a Lawn Mower Blade
Lawn Mower Parts
Lawn Mower Blades

66 Comments

  1. Alan Ochsner
    on July 21, 2016 at 11:19 am

    I don’t have a mower just a string trimmer.

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  2. AnnaMay Gatcomb
    on July 21, 2016 at 11:30 am

    How often should they be changed????

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    • William Miller
      on July 21, 2016 at 5:35 pm

      IF you have a brain, you should get at least five years out of your blades. Mine are 7 years old, and have mowed 3 acres in Alabama all that time. Why? Cause I remove deck twice a year, sharpen and balance the blades. I do not run “WFO” very often, and over any bare spots I mow at idle. I wire brush and paint the blades when I take them off. And put on my second set. My blades are too sharp to run your finger over, unless you like to bleed. Use your head, and your lawn tractor will still look like new after 10 years.

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      • Don
        on July 23, 2016 at 7:24 am

        Wow. Just wow. Thank you for that detailed and dare I say, thought-provoking reply. If only everyone could be as intelligent, this world (and our lawns) would be a better place.

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    • Drew
      on July 22, 2016 at 7:44 am

      When the edges on the ends of the blade no longer are square. When the edges are rounded.

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    • Drew
      on July 22, 2016 at 7:48 am

      …or when they get bent or no longer balanced. Forget sharpening and balancing…just get a brand new blade for about $10. Or tear up your good engine with bad vibration!

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  3. Jeff
    on July 21, 2016 at 11:36 am

    I hand sharpen them with a file each year through about the 4th year then replace them.

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  4. Patricia Callari
    on July 21, 2016 at 11:41 am

    I live on a corner, my lawn is not big but big enough. I sharpen the blade after one year. Works fine for me!

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  5. Glenn Callies
    on July 21, 2016 at 11:42 am

    I replace them when they can’t be sharpened anymore.

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  6. Josh
    on July 21, 2016 at 11:42 am

    Rocks. Lots of rocks in N.W. Colorado high country.

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  7. Richard
    on July 21, 2016 at 11:53 am

    Sharpen blades as needed, when they get too thin & start to bend, then I get new ones.

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  8. RONN HAMPTON
    on July 21, 2016 at 11:54 am

    I wire-brush and sharpen my blades twice a year. I’m 71 and have done so forever! I may have purchased a blade (just 1!) many years ago, but don’t really remember doing so.
    I have only my 1/2 acre lawn.

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  9. robert willis
    on July 21, 2016 at 11:55 am

    Normally change blades twice per mowing season.

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  10. John Hadley
    on July 21, 2016 at 12:00 pm

    Small lawn I replace the blade every spring.

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    • Andy pierce
      on July 21, 2016 at 7:52 pm

      you are throwing your money away. must be nice to be rich. I have same blade for 8 years and a little filing at the end of the season and wallla!!!

      Reply to this Comment

  11. John Drzymalla
    on July 21, 2016 at 12:11 pm

    3 times per year.

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  12. Terry Smith
    on July 21, 2016 at 12:17 pm

    Only when needed.

    Reply to this Comment

  13. Jim
    on July 21, 2016 at 12:20 pm

    I have a blade sharpener tool so a set will last almost all mowing season if it weren’t for the sand in central Texas .

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  14. Gene
    on July 21, 2016 at 12:24 pm

    I used to think Mower Blades were a gimmick, a rip-off, one day I was at my Uncle’s in E. Florida. He is a Welder and has his Journeyman’s license, he worked for NASA for many years. I told him how I felt about Mower Blades and asked him what he did about his as I knew he could make his own. He told me that he had tried every different metal and metals heavy in alloys, He told me,”I even made a set out of Stainless Steel,” But, the sand still wore them out. Go Figure.

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  15. David Kiesel
    on July 21, 2016 at 12:28 pm

    Are you asking how often I sharpen blades or replace them? It’s a totally different question?

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    • Turner Anderson
      on July 21, 2016 at 2:10 pm

      Replace would be the question, agreed there is a difference, since some don’t even bother sharpening or have tools to do so.

      Reply to this Comment

  16. Gregory Walker
    on July 21, 2016 at 12:31 pm

    I sharpen up my own blades….and make sure the blade is balanced..when it wears out…I will purchase a new blade..Greg

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  17. Melvin Mundis
    on July 21, 2016 at 12:46 pm

    I mow with a 60″ commercial duty mower and have two sets of blades which I change and/or touch up about 4 times a year unless I hit something. I mow two properties ( about 5 acres) and sometimes for a church and an elderly neighbor.

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  18. Kent wilson
    on July 21, 2016 at 12:58 pm

    Have two sets of blades. Depending on how many times I cut per week. I’ll put a sharped set on an then sharpen the ones I took off so there ready for the next change. Of course the blade are wired wheeled clean, sharpened and balanced!

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  19. Ernie
    on July 21, 2016 at 1:16 pm

    As a retired toolmaker I do have some experience on steel. I sharpen and balance my own mower blades about 3 times a year given my lawn is a good two acres. Just need to remove all branches, stones, etc. form the lawn before cutting. Actually I first weed whip while removing all rocks etc. After I weed whip I then mow.

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  20. Roy Cox
    on July 21, 2016 at 1:26 pm

    I have several sets of blades that I rotate during the year. If a set gets too many nicks or gets bent I always have a new set to put into the rotation. After removal, I clean the blades, inspect and sharpen them. I balance them using an Oregon Precision Blade Balancer. Now they are ready again for the zero turn.
    Thanks…Roy

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  21. Dave Dolinar
    on July 21, 2016 at 1:28 pm

    Unless they show signs of Damage (cracks or bent)

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  22. Keith Murray
    on July 21, 2016 at 1:59 pm

    Blades usually last about 15 hours running time before I swap them out for a sharp set. Can most of the time sharpen them about 3-4 times then replace.

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  23. John Studer
    on July 21, 2016 at 2:19 pm

    I sharpen my blade every spring. I will continue to do so until the metal is down to where it could hit an object and a piece might come off causing injury to others, property or self. Sometimes blades will shorten due to picking up sand and rock, then it may be necessary to change them. If a blade gets bent by hitting an obstacle and the mower shakes, it may be time to replace your blades (this may cause a bent crankshaft also). If you sharpen your own blades, don’t forget to balance each one.

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  24. Michael Galorath
    on July 21, 2016 at 3:05 pm

    I sharpen and balance it once a year. Mower is 20 years old

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  25. Tim W
    on July 21, 2016 at 3:07 pm

    Some tips. First, sharp blades usually cut the first half inch from the tips. With mowers that have multipule blades that overlap each other while spinning, its important to keep the edges sharp to avoid uncut grass between the blades. For 3 blade setup, always keep the best blade on the middle spindle to keep this from happening. For most homeowners the time to resharpen the blade varies with the cutting conditions. In dusty, sandy, or stoney areas,the blade will need sharpening 2 or 3 times or more in a cutting season because the dirt, small rocks, and sand act like sandpaper to the blade edge. Most people can go a season before resharpening is needed. Good rule of thumb for blade replacement, if more than 1/3 of the blade width has been grinded away from resharpening, then its time to replace with new. Hope this helps everyone.

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  26. Dave Emerson
    on July 21, 2016 at 3:38 pm

    I am mowing about 3 acres. The old Sears 42 inch lawn tractor would need a blade replaced several times a summer due to being bent beyond repair. I think they were pretty poor quality. My new Toro 42 inch zero turn is on its 4th year and have not needed replacement yet. Sharpen and check the balance 2 or 3 times a summer.

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  27. Dale Eatinger
    on July 21, 2016 at 4:20 pm

    Wow, I never thought that deeply into mower blade replacement. I remove and sharpen the mower blade once a year, in the spring before the first mowing, and when they look worn out I get another. The rider gets the same treatment.

    Reply to this Comment

  28. Daniel Alvies
    on July 21, 2016 at 4:38 pm

    We have three mowers two riding and one self propelled. I sharpen when needed. Buy new blades when needed.

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  29. OX
    on July 21, 2016 at 4:49 pm

    Never sharpen. Have a “BAD BOY” it came with hardened weld overlay on the cutting surface. Had mower three years, gravel driveway, 3 acres to mow in yard. I clean the deck every fall and they look new.

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  30. George Riley
    on July 21, 2016 at 4:52 pm

    Sharpen every 20 hours. Replace as needed, maybe every 60-80 hrs. Mowing 1/2 acre of ST Augustine.

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  31. Valéry Vanderpert
    on July 21, 2016 at 5:12 pm

    I change the blade as it approaches the wear limit or what is distorted or suffered any shock and I sharpens every two or three mowing

    Reply to this Comment

  32. Will
    on July 21, 2016 at 5:13 pm

    I replace them when they are worn out as per the owner’s manual of the machine. I do a little bit more cutting than the average person and I try to sharpen them once or twice per year.

    Reply to this Comment

  33. Steve Hopkins
    on July 21, 2016 at 5:20 pm

    1952 Gravely L with left hand mower, I hard face the edges & refit, replacements are no longer available

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  34. Alan Schneiderman
    on July 21, 2016 at 5:21 pm

    I replace the blades when they can’t be sharpened any more.

    Reply to this Comment

  35. Joan Chain
    on July 21, 2016 at 5:29 pm

    I have a very small lawn, and, do not need to replace blades that often.
    Most often, the blades are also used to chip up leaves in the fall.

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  36. Lance
    on July 21, 2016 at 5:48 pm

    I sharpen the mower blades on the riding mowers and the rotary push mowers every year using a bench grinder. I replace them about every 10 years or so. The blades are heavy duty and I do not run over any solid objects. My land leveling activities occured about 50 years ago.

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  37. Joseph Robichaud
    on July 21, 2016 at 6:34 pm

    I mow at least 17 yards a week lots of them are sandy which wears out the blades far faster.
    The OEM blades only last 20 hours and where worn in half.
    Switched to Oregon G6 Gator blades and I can go 40 hours before they need to be sharpened, and I can get three sharpenings before there worn out enough to replace.
    There 1/4″ wider, .050 thicker and far harder, which you will see when you go to sharpen them.

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  38. JAMES WHITAKER
    on July 21, 2016 at 6:45 pm

    KEEP THEM SHARP, KEEP THEM BALANCED,AND IF YOU DO HIT SOMETHING HARD…CHECK THEM FOR STRAIGHTNESS…. MEASURE FROM DECK IN ONE SPOT, ROLL AROUND OTHER END AND IF IT IS OFF MORE THAN A 1/4 INCH BUY A NEW ONE AS VIRTUALLY ALL THE BLADES NOW DAYS HAVE TO MANY WAVES DIPS AND ANGLES TO PROPERLY STRAIGHTEN OUT FOR SAFE USE….

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  39. Mike Vincent
    on July 21, 2016 at 6:47 pm

    I have a lot to cut but I only change them about once a year. Lots of bahaia grass to cut. That is really rough on blades. Spring is a rough time to cut because of all the new weeds and grass. My machine takes 3 blades, I pull them and sharpen then every so often.

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  40. Eddie Robinson
    on July 21, 2016 at 6:54 pm

    About ever three yeras

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  41. Mike
    on July 21, 2016 at 7:12 pm

    I’m a lawn pro. Blades get swapped out every 8-10 hrs of actual machine hrs. I have at least 10 sets for each mower

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  42. Robert Hartshorn
    on July 21, 2016 at 9:55 pm

    I have 3 sets, one set being mulching blades, for both the riding mower and push mower. I keep them sharpened and will change blades about 15 to 20 hrs. This has proved satisfactory.

    As far as replacing them, hardly ever. As long as they are sharpened and balanced properly, they are okay.

    Reply to this Comment

  43. Steve Dobbs
    on July 21, 2016 at 10:25 pm

    I was sharpening every mowing and replacing once a year. Since, I purchased a set of gator blades by Oregon from Jack’s. Now sharpening once every month or two, this set going thru their third season and still shows little wear. May never have to buy another set.

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  44. gerald Pushard
    on July 21, 2016 at 11:01 pm

    Your demo didn’t mention removing the spark plug wire from the spark plug
    before removing the blade…an important safety tip..Whenever doing any work under the deck be it cleaning dead grass or removing the blade. remove the spark plug wire..

    Reply to this Comment

  45. C Caldwell
    on July 22, 2016 at 5:05 am

    I have mine hardfaced by a welder and they last me 4 to 5 years.

    Reply to this Comment

  46. Tony
    on July 22, 2016 at 9:48 am

    Over time,sand,dirt,and other yard debris can erode the blade, causing the metal to weaken and become paper-thin. If you notice this, replace the blade, to avoid breakage during mowing.

    Reply to this Comment

  47. Enid
    on July 22, 2016 at 11:36 am

    Never, because the ones my lawnmover have are ok!

    Reply to this Comment

  48. Johnny Fusco
    on July 24, 2016 at 8:10 pm

    I’m in the lawncare business and sharpen my blades every 12-15 lawns.You gotta keep em sharp to maintaining a nice lawn.

    Reply to this Comment

  49. John Phillips
    on July 24, 2016 at 9:11 pm

    I live in north / central New Jersey and have Zoysia grass. I keep my grass cut high and water and fertilize it often to achieve a thick and beautiful lawn. But I have to sharpen my blade once every two weeks and change my blade twice a year because the Zoysia grass wears them out. It’s a little expensive but it’s worth it to achieve a gorgeous lawn.

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  50. Rodney Johnson
    on July 25, 2016 at 9:17 am

    I sharpen every day. it takes me 7 minutes to sharpen and balance my blades. They turn fast so I keep them sharp and I mow very fast. Mows come out perfect. I replace blades twice a year, still plenty of life left, but lift is less from narrower blades, so I have to slow down some. I only buy Toro commercial blades as they are thick and hard, and take lots of abuse.

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  51. Marvin Lamar Williams Jr
    on July 25, 2016 at 11:35 pm

    2.5 acres just easy to replace them

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  52. Jerry
    on July 26, 2016 at 2:45 pm

    Down here, we have lot a rocks. Northern Arkansas. Some years I get away with one set, but other years 2 sets. I’m mowing with a 520 H from Toro 1996 model. When I lived up north, this machine worked year around, blowing snow in winter and mowing in summer. And I’m mowing my neighbors yards, just to have something to do.

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  53. Kermit
    on July 29, 2016 at 4:18 pm

    I am a disadvantaged or handicapped 74 year old veteran and moving around is difficult. Several times per year I will move my wife’s car out of the garage and put my 50″ mower on the lift and inspect the three blades. If there are bends or dull places I will take them off, straighten, sharpen, balance them and put them back on. My yard is pretty rough and I use this mower to mow the grass and also to brush hog a little more several times each year. So my yard gets a little larger before the year is over. I bought it September of 2013 and it is still going strong. Have replaced deck belt about three times and I will have to replace the propulsion belt before this year is over. May have to get some help with that but after removing the deck I will probably weld a place to hook a come-a-long to turn the machine up on its side. But if that doesn’t work I will as for help. My closest neighbor is a 1/2 mile away in either directions but I believe either would offer a hand if they knew I needed help.

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  54. Jaakko Paavola
    on July 31, 2016 at 8:55 am

    I replace the mower blades only when I see they are worn. Jaakko

    Reply to this Comment

  55. Tom Schulte
    on August 14, 2016 at 11:02 am

    I rotate them yearly, installing with mulcher blades at Fall time.
    Replacing–this is not a time issue – it one of wear, and gut feeling.
    I would replace them if they have major nicks, cannot be balanced, or if there is something ‘suspicious’ about them.
    I can always make more money, but body parts are harden to come by!

    Reply to this Comment

  56. Bill Gould
    on November 21, 2016 at 2:34 pm

    I have a 1/3 acre lot and mow once a week. I have 5 blades, keep them sharpened and change every week. Saves gas and is good for the grass to cut with a sharp blade.

    Reply to this Comment

  57. AL Seaver
    on November 21, 2016 at 5:06 pm

    I have 3 sets for one of my zeros, and four sets each for my other zero and Scag 3-wheeler. I also have my own sharpening machine. I still only change them out whenever I happen to think of it, but I immediately resharpen them as soon as they come off so they’re ready when needed. I only buy new ones when absolutely necessary.

    Reply to this Comment

  58. MowPro55
    on March 18, 2017 at 11:51 am

    I have Bahaia grass and I sharpen my 22 inch blade and balance every other cut here in the sandy Southern soil I use a 30 degree bevel cut on a belt grinder rather than a convex cut on a round wheel type grinder. It makes for a more durable edge as it leaves more metal in the middle rather than remove the metal in the middle like a round wheel would do as it sharpens. I make the edge razor sharp and I balance on a Magnamatic GC 1000 blade balancer. On My commercial zero turn blades I sharpen about 4 times a year since it is only used on my personal lawn as they are more durable blades and hold a sharp edge better with .250 inch thick Marbain steel blades.

    I am a lawn care professional so I am sure it may be a bit of overkill for some but I always get good complements on how lush and green and healthy my lawn looks. One of my tricks that most people over look and even so called professional lawn cutting crews tend to overlook is having razor sharp blades to cut the grass ….my blades cut the grass rather than tear it. Check it out. Look it up on websites or google it. What most consider to be a sharp blade is dull compared to high end commercial cutting standards. That is why on upscale lawns a set of freshly sharpened and balanced blades almost always goes on before the lawn is cut. Trust me…..I know……I used to cut them for a living. We kept our blades sharp and balanced and never let them get dull. The lawns look nicer and more professional. It is work……yes it is work, but the end result of a nice evenly cut manicured lawn is certainly well worth it.

    A sharp blade cuts the grass rather than tears it and razor sharp is how you want it installed. Then why aren’t they razor sharp from the factory…….one reason and one reason only and it is called …..”LIABILITY”…..You can just imagine all the lawsuits from consumers over that one. I have a few neighbors who have learned and caught on to the secret of a sharp blade cutting the grass.A cut blade of grass rather than a torn blade of grass allows for less moisture evaporation, it heals quickly, and is more disease preventive. It is equipment maintenance…..a maintenance that many people over look and even fail to do as often as they should. Your lawn will look better and be more healthy. There are lawn cutters……yes guys that ride around with a truck and trailer and cut lawns and you may get a sharp blade on your lawn if you are the first one or two in line but Professional lawn crews have multiple sets of freshly sharpened blades ready to be installed in the field as necessary because they know it is healthy for the lawn looks and the cut also looks more professional.

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    • Turner Anderson
      on March 23, 2017 at 11:49 am

      Thanks for the great info and tips!

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    • LawnPro35
      on August 18, 2017 at 7:03 pm

      I also cut high end lawns for a living and what you are talking about having fresh and sharpened blades is so true. We also carry multiple sharpened and balanced sets always ready to be installed as necessary. IF more people would learn the secret of sharp and balanced blades they would have less lawn disease and a healthier greener looking lawn. Thanks for the info.

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