Oh, a good one'll stick around for years-way longer than you'd think! I have a Warner stainless steel putty knife that I've used for 4 years now, and it still works like the day I bought it. Let me break it down: if you take even basic care of it (wipe it off after use, don't leave it out in the rain), a high-quality putty knife can easily last 5-10 years. My neighbor's a contractor, and he has a Stanley one he's had since he started his business 7 years ago-still sharp, still no rust, handle's not loose at all.
The key here is the materials. Cheap knives rust or bend after a few uses, but quality ones have thick, rust-resistant blades (stainless steel or coated carbon) and sturdy handles. I once forgot my good knife outside overnight during a light rain-panicked the next morning, but wiped it off, and it was totally fine. A cheap one would've had rust spots by noon.
Of course, it depends on how much you use it. If you're a DIYer who patches a few holes a year? It'll last decades. If you're a pro using it every day? Maybe 5-7 years, but that's still way better than replacing a cheap knife every month. I had a friend who used his high-quality knife for drywall jobs 5 days a week-he finally replaced it after 6 years, and only 'cause he accidentally dropped it off a ladder (even then, it still worked, just had a small dent).
The only time you'll need to replace a good one is if you really abuse it-like prying up nails with the blade (don't do that!) or leaving it in a puddle for weeks. But with normal use? It's a tool you'll have in your toolbox for ages. Trust me, I've gone through 10 cheap knives in the time my good one's lasted-total no-brainer.
putty knife from hanke tools
