In the '70's, my dad bought a Buck 112. He was an avid fisherman and custom bike builder. As far back as I can remember, he wore that knife on his belt every day; I have a picture of him on a road trip from '74 and it's just visible.
He never babied or was even particularly careful with the knife; he saw it as a tool and wasn't afraid to use it as such. That knife gutted salmon, pounded tent stakes, opened cans. It got used as a prybar, screwdriver, guywire peg, and even occasionally as a knife. After at least 15 years of daily wear, the sheath gave out. He tried pocket carrying for a while but couldn't get used to it (with reason; it's a heavy knife). For a while he put it away in his tackle box, but at least every couple of days I'd see him reach for it before he remembered.
When I got my first job shortly after (I was around 13-14 at the time), one of the first things I bought was a nice custom sheath to give him for his birthday. Now, at that time, my dad was not a man of many words or open emotion; but I'll tell you this: with one exception (which I'll get to in a minute) I never saw him without that sheath on his belt again, and that said a lot to me that I don't think he could.
A few years after that, we were on a road trip in a pretty remote area and had to perform an emergency tire patch (this was before anyone other than big city lawyers and brokers had cell phones). The Buck got pressed into service as a tire bead lever. As we were putting the tire back together, the blade snapped in half. (I cringe now, thinking about all the things I saw done to that blade over the years, but I'll say this: it got the job done and got us home.) Once again the knife got put away for a while. At first I bought my dad a 110 to replace it (I didn't even know the difference at the time - the 112 wasn't readily available). He used it sometimes, but he really felt it was too big for everyday tasks. So without telling him, I wrote Buck a letter asking if they'd fix it. I told them that it broke while doing something that knife was never designed for; it wasn't a warranty issue, I'd pay for the repairs, I just wanted it fixed. They replied, telling me to send it in and they'd let me know what they could do. Two weeks after I sent it off, they sent it back with a new blade, tuned and polished up like new - at no charge.
About a year ago, my father passed suddenly. About a month and a half afterward, my mother came to me and said, "I've been looking for this for a while; I finally found it. Would you like to have it?" And in her hand was The Buck, still in its sheath. Uh, you bet your... That is, of course I would.
The sheath is starting to show its age; it's almost 20 years old, after all. Now, I considered keeping it in the safe for a minute, but after everything, I don't think Dad'd be happy to know it was rusting away in a drawer somewhere. So I bought a new sheath and have been wearing it most days. I'm more careful with it than he was, but by God it's gonna get used.
So no, that's the one knife I own that will never be sold. The only way that Buck leaves me is by passing to my daughter when I go.
I'll add pictures when I get home.