In a previous life when I learned a 'real world job' (industrial toolmaker in Germany), our master used to yell: "Not as precise as possible, only as precise as necessary!" (essentially the German version of "Cha Bu Duo" I guess?) when we spent too much time on one thing.

This is exactly why tolerances exist which are clearly defined upfront for every measurement. Inside the tolerance is by definition 'good enough', outside is not. Very simple and leaves no room for discussion.