I started out with 12 mg using egos and clearomizers. As I've moved up the ladder to RBA's and a Reo, I've continued to use 12 mg. Only time I over-did the nic was trying to lung-hit a sub-ohm, dual coil, wide open airflow atomizer, which made me a bit woozy for a few minutes. Just this week I mixed some 6 and 12 mg juice to make 9 mg juice, and I can tell the difference, I'm going through more juice with just that tiny change.