Most of what I do, have done, is remodeling and small scale commercial. No machines/boxes. Generally push for a level 4-5 finish in three passes and minimal touch-up. So the methods have become oriented toward filling cliffs and canyons. Uneven sheets and surfaces, blending into existing ... blah blah blah and so on & so forth.
2" & 4" Knife, for those BS spots where a 6" won't fit. Rare to use on new construction.
6" for inside corners (corner knife occasionally - whole other topic LOL) and paper on butts. All inside corners are skimmed with the 6" as well as screw holes initially. Will often 2-3 coat with what ever knife is in my hands. Long pass vertical build up over all in a row and then a good wipe.
8-10" knives for filling flats (mesh) and corner bead. Few reason over a 6", they hold more mud per swipe, can get a rounded build up on the tapers (closer to flush/flat sooner), gets a longer feather going sooner, and with corners avoid the high angles back to the flat. As a finish carpenter I CURSE corner bead.
12" all skims in the field.
A bit unconventional, but for remodeling it has become the best way to conserve movement by me.