You'll get animators pulling all sorts of shenanigans. One I learned about recently is when animating on twos (or threes or fours or...) they'll interleave when

You'll get animators pulling all sorts of shenanigans. One I learned about recently is when animating on twos (or threes or fours or...) they'll interleave when different elements move. E.g. character A moves on odd frames and character B moves on even frames. This is the same amount of work but feels smoother and less mechanical when watching it.