Quite a few times I read on this site about calluses. How they are an important part of being a guitarist. How they help one's playing, how they really can't be avoided.
Fair enough, when I started learning at age 11, I developed terrible things on my fretting fingertips. Due mainly to having a guitar that had an action far too high for even slide playing, and strings far tighter than I've ever used since, but also due to pressing too hard, as most beginners do.
However, after learning how to set up guitars properly, and discovering lighter strings, although playing and teaching just about every day, haven't had a callus in 50 years. Lighter strings on guitar, but on bass, going down to low B .130s, so maybe the gauge isn't that relevant.
I feel that calluses are counter-productive, in that there's less feeling in fingertips, and hammering on and pulling off is more effectively done using real skin.
So, are they something most players get, and put up with, why do they materialise, are they useful things to have? I can't remember any of my students having them. And - are they of relevance to string bassists (or any other string players)?