As the price goes up, the less I'm willing yo put up with. If it's something I can fix, and I otherwise like the knife enough, I'll keep it.
Example, I love the look, blade shape, and ergonomics of my A Purvis Progeny v2. However, it came with an overly strong detent, mediocre action, and gor some reason, a steel backspacer on a knife with near linerless carbon fiber handles.
I took it apart, lightly adjusted the lockbar tension, removed the backspacer, and cleaned out the increasingly more common black viscous gunk in the pivot. Put some nano oil in it, and it's great. Definitely worth the time and effort.
I don't like uneven grinds. If a $50 Civivi can get it right, a $200 knife should also be able to get it right.
I also don't like noticeably off center blades. While often correctable, this is a sign of poor quality control snd makes me wonder what else might have been missed and/or done incorrectly.
TL;DR There are limits on what I'll put up with, but I don't care how great the customer service is, I shouldn't have to send the knife in when new.