How long a kitchen knife lasts depends on its material and how it is cared for, and can range from a few years to several decades. A knife that has stopped cutting has not necessarily reached the end of its life: in most cases, resharpening brings it back. On this page, Hayashi Hardware, a knife shop founded in 1872, explains how long knives typically last, what sharpening can and cannot fix, and the signs that it is time for a new one.
How long knives typically last
| Type of knife | Used without sharpening | Used with regular sharpening |
|---|---|---|
| Mass-market household knife (soft stainless steel) | Stops cutting within six months to a year | 5–10 years. It is finished once the blade is worn away |
| Quality stainless knife (AUS-8, VG-10, etc.) | Sharpness drops off within 1–2 years | 20–30 years or more |
| Carbon steel (hagane) knife | Prone to rust, so its life is often short | Decades, depending on care. A craftsman-made knife can last a lifetime |
What makes the difference is whether you sharpen it. A knife made from good steel loses a little metal each time it is sharpened, and you can keep using it until the blade becomes narrow.
"End of life" is not the same as "stopped cutting"
- Fixed by sharpening: the blade slides off tomato skin, onions make your eyes water, chicken skin stretches instead of being cut. The edge has simply become rounded, and resharpening restores a like-new edge
- Fixed by repair: chips and nicks in the edge, a wobbly handle. Resharpening or a handle replacement lets you keep using the knife
- Cannot be fixed (time to replace): the blade has been sharpened down to nearly half its original width / the blade is bent or broken / deep rust has eaten into the steel / the knife was heated over a flame and has lost its hardness
Signs it may be time for a new knife
- It goes dull again within 1–2 weeks of resharpening (the edge has become too thin)
- The blade width has worn down to two-thirds of its original width or less
- There are deep rust pits (pitting corrosion) in the blade
- The blade is warped and no longer meets the board evenly
- Even with a new handle, the tang (the part inside the handle) has rusted so thin that it cannot be fixed securely
Three habits that make a knife last
- Wash and dry it right after use: this prevents rust and handle damage. How to wash a kitchen knife
- Give it a light sharpening on a whetstone once a month: sharpen when it starts to feel a little dull, rather than waiting until it stops cutting. You remove less metal and the knife lasts longer
- Have it professionally resharpened every six months to a year: this restores an edge angle that home sharpening has thrown off. Resharpening service
Habits that shorten a knife's life
Cutting frozen food or bones (chips), the dishwasher (damage to the handle and blade), glass or stone cutting boards (wear on the edge), heavy use of pull-through sharpeners (a ragged edge), and heating the blade over a flame (loss of hardness). For details, see "What not to do" in our complete guide to knife care.
If you replace it, choose a knife you can keep sharpening
Rather than buying a knife in the same price range every time one wears out, a knife you can resharpen and use for 20 years works out cheaper in the long run. We carry the Sakai Takayuki Kurokage in VG-10, the INOX Wa in AUS-8, and Hayashi Hardware originals, mostly in Aogami carbon steel. All of them come with free first resharpening (then from ¥1,500 per knife; mail-in available within Japan).
Frequently asked questions
Q. How long does a stainless steel knife last?
Without sharpening, the edge fades within six months to a year on a mass-market knife, or one to two years on a quality one. A quality stainless knife that is sharpened regularly, however, can last 20 years or more.
Q. How often should I sharpen?
For home use, a good guide is sharpening on a whetstone about once a month, plus a professional resharpening every six months to a year.
Q. Is a chipped knife at the end of its life?
In most cases, resharpening can fix it. The deeper the chip, the more metal has to be removed, so it pays to bring it in early.