Highest quality ever made, cheapest Chinese knock off on the market, custom made, or off the rack, the most important thing is inspect, clean and maintain!
We have talked and typed for years about lint in guns and magazines - why wouldn't a carry knife be any different? I use my knife daily, and look at it at least once a day. Weakly I clean it of lint, dirt and other pocket crud. I will even run it through the parts washer or spray with brake cleaner and then re-oil.
Your knife is nothing more than a self defense that doesn't go bang, so why shouldn't we treat it the same as the one that goes bang?