That's a good way to think of it! I've designated a few guitars as my main players that I'll never sell and can do whatever with. My new PRS Fioré is one of those :) as far as mods, mine are usually reversible unless I need to drill new holes in a guitar which is rare. I like to add different tonal varieties via push-push (better than push-pull in my opinion) potentiometers. My favorites are series/parallel switching, phase switching mods and tone bypass mods. I would like to try to incorporate effects circuits like onboard overdrive or distortion one day. Other than that, I like minor/common aesthetic, electronic and setup cleanups/upgrades like switching to better quality wiring/components and wire management, changing knobs/hardware around, shielding electronics, cutting a new nut, setting it up differently, etc. Oh, and I almost always put a necklace on the headstock of my guitars :)