Used to eyeball every drum adjustment, now I keep a $9 set of feeler gauges in my shirt pocket
After I cooked a set of rear shoes on a 2004 Tacoma last month because my "by feel" method had drifted about 8 thousandths, I started checking every drum with gauges before it goes back together and comeback jobs dropped to zero, so what cheap tool did you put off buying way too long before it saved your butt?
That sinking feeling when you realize your hands lied to you for years is the worst. Feeler gauges are one of those cheap things that make you wonder why you didn't grab them sooner.