Good a arms
Good swing arm
Good shocks all around
Tight bushings
Tight tie rod ends
Good bearings
The shit that gets over looked. Like the rear shock hiem bearing things, the linkage bushings, swing arm bearings, stem bearing and seals, brakes not frozen, good rotors, and what ever else you can find. I see so many bikes that people have never serviced these parts. I try to make it yearly to change out these parts. If I have to think back to when I might have done it and can't remember then it's about time.
It gets expensive the first time to do everything but once done you'll see what last and what doesn't. Then you can figure out service intervals for stuff.