I have a German-made clasplock, don't know what brand (IIRC it had a brand on the blade but I polished that off so many years ago...). As soon as I got it home I reshaped the tang for inertial opening and it's survived hundreds of thousands of inertial openings since then -- maybe millions -- I carried it every day for maybe fifteen or twenty years, used it for everything ... I think I tightened the joint twice in that time ... now retired since I saw the Light and no longer carry folders, but if I were still a heathen I would expect it to keep going for the rest of my life. That's a factory-made knife and it wasn't at all expensive by the standards of this forum. I think I paid about $30 for it and that was about 1974-76. It has a brass bolster (only one), rosewood scales, steel liners, and a 4" (10cm) blade that originally had a straight spine. I rubbed some linseed oil into the scales a number of times over the years, tightened the joint twice (with a hammer), and kept it sharp -- no other maintenance or repairs.
I've broken some knives, too, but they were mostly very cheap knives. Broken a little off the tip of a number of knives but not that one; it has a strong point. I've lost more knives than I've broken. Long ago I made a leather pocket sheath with a clip for that one so I wouldn't lose it, and I carried it in that sheath clipped inside my back pocket for many years.
-Cougar Allen :{)