>warning light sender has this to say about torquing:

Well, for regular bolts/screws, with experience one does develop a
"mechanic's feel," where you can feel when the bolt starts to stretch
and full "torque" is achieved. (I quote torque because it is an
indirect measure of clamping force, which is the real concern).

Pipe fittings are a bit different, since they seal instead of clamp, so
the feel is completely different. Most people tend to vastly
overtighten them. "Hand" tight, plus a quarter turn is probably a good
start. If it leaks, give it another quarter turn.