Bushings, the smallest part of a setup, make a world of difference. I rode nothing but stock bushings my first couple years skating over a decade ago, and it was awful. Most stock bushings are better nowadays, but they're still pretty high in duro and I don't think most people weigh as much as me, haha.
Bearings (for the most part) don't matter as long as they're not corroding.
These two small tidbits could have saved me trouble and money years ago.