I’m an inveterate tinkerer and have messed with almost every bass that I’ve owned, even one of my custom builds (replaced the pickup, knobs and fitted a pickguard). The least messed with have been my old Roscoe Beck signature (perfect as it was, except I eventually fell out of love with the neck width) and one of my current Maruszczyk custom builds, but even that has replacement knobs (Sadowsky style) and a couple of under layers for the transparent pickguard for a change of appearance. Probably the most savaged was my first Fender US J, I replaced the pickups with DiMarzio super Js, fitted an East preamp, put on a D tuner, recessed strap locks and a replacement PG. Then there was the Fender P Roadworn that had an extra P pickup fitted, the neck stripped and a replacement PG. I think I’ve got better over the years and changes tend to be cosmetic. However, guitars are another matter altogether, my 2 electrics have had all manner of changes made, to the point where the Telecaster only has the original neck and tuners, neck plate and PG, everything else is different (it is now perfect).