I've seen Rick change the title to this one a few times, but I'll give it a shot:
Belts - I stopped buying a billion belts in different grits due to some experienced makers showing me grit formulas that worked well with each other. Namely, Steve Johnson's 50grit to 400grit jump, and Ray Laconico's 60 grit to 180, then fine scotchbrite jump.
Which leads to -
Machine finishes - I've always hated the look of a horizontal 400 grit hand rubbed blade, and I hate doing it worse. It's not that I can't, I've been restoring different knife, and non-knife projects for years, I just like the look of a machine finish on a knife better. I like the repeatability, and the ease of maintenance. For me, it's the way to go.
Sharpening - On my first knives, and the bazillion other factory knives I've sharpened, the edges were relatively thick. This meant hours of sharpening with various gizmos, and expensive stones. I've learned to grind THINNER in the first place, and I've reduced sharpening time to mere minutes (sometimes seconds) with just a few inexpensive hones. Reduces screwups during final sharpening too. I've scrapped whole knives because I marred my nice finish irreparably by spending a F'ing hour on grinding some fat bevel with a DMT coarse hone.
(note* I've stopped using a belt for sharpening. Sad to see all that hard work/money turn a hot rainbow of disastrous colors.)
Safety - Lungs feeling like punching bags, and fingers chopped up from helicoptering blades in drill presses will make you take safety seriously. In the beginning, knives were first on my mind, then safety last. Now, It's the opposite. With no knifemaker and his parts functioning, there can be no knives.
Steel type - I'm learning right now that I don't really want to deal with, or babysit another 10x series, or A2 carbon steel knife ever again. I can't seem to keep the rust off of them. Maybe it's this good old Kentucky rain or something. Specialty stainless is in my near future.
Oh....and masking tape is your friend.