The brake pad wear gauge in my head finally clicked after 15 years of guessing
Last Tuesday I was bleeding a set of old cantis for a neighbor's kid and I realized I've been checking pad wear by feel this whole time. Just pressing the lever and eyeballing the gap. It worked fine for me but I could never explain it to anyone else. Then I had the kid hold a credit card next to the rim while I squeezed, we used the card edge as a straight reference and suddenly the whole thing made sense. Anyone else got a lazy mechanic trick that turned into a teaching moment once you had to break it down for someone new?
That credit card trick is smart because it gives the kid something to compare against instead of just saying "looks about right." What took it further for me was having them squeeze the lever while I watched the card edge, then swapping. That way they feel what too much gap feels like before it gets fixed. The feel part is the thing nobody can teach you in words, so you have to build a reference they can see first. Same deal works on v-brakes and even drum brakes if you're patient.