I know that this is a zombie thread that's about 13 years old, with some now-gone-but-not-forgotten members (thinking of norm) but I will point out that in my experience one tends to lose knives before one wears them out. Case in point (two puns there, in memory of Mr. Atkinson), a few years ago when I could still run 6 miles, I found a Swiss Army knife on the road. Aluminum scales. Damaged either from falling from a car or bike and being run over. Took it home, opened up the squashed parts, and it's perfectly serviceable as a cutting tool. Less so as a presentation gift. Its pretty rough. But when the original owner dropped it, it was likely far from worn out or broken.
It looks like this, only lots worse:
View attachment 398119
The think lists for $46 these days, so I probably wouldn't buy one for myself.