Engineers generally use pi=e=3. (Obviously not exclusively; there are times for more precision) Four digits is almost always more than you need, though. If yo

Engineers generally use pi=e=3. (Obviously not exclusively; there are times for more precision) Four digits is almost always more than you need, though. If you need more, you probably: - failed to make something balanced - missed an opportunity to have something be self-calibrating - used open-loop instead of a feedback system - didn't taper a hole - are measuring the wrong thing - ... or similar.