All right, if I bring audio equipment or musical equipment to someone's house or a venue, how can figure out how much power my equipment will use up (or if it fluctuates, then range of power) and what the max load is? I've found bits and pieces to this answer, but not a simple, straightforward one. Help would be more than appreciated (or I'll keep breaking circuits).

-Matt

Ps: I realize "power" is a vague term as well, sorry...

An Amprobe can tell you current of each, or total current for your equipment.
Try to plug in different circuit.
Either use less drawing equipment, or add circuit.
80% of a 20 amp circuit is 16 Amps.
80% of a 15 amp circuit is 12 Amps.
If the wire is #14, it has to stay on 15 amp circuit breaker, increasing breaker size can be dangerous.