Q: I was just wondering... when you say something like 12 repitions in a set, say, for arms, is that 12 reps per arm or 12 total (6 each)?

A: It's 12 repetitions for each arm. If you do barbell exercises, that means 12 reps total (because both arms are working in each rep) and if you do dumbbell exercises, then 12 reps for each arm. Either way, each arm does 12 reps per set.