Primer puffs is a long story dating back to my KR808D usage. But lately I find myself taking one or two smaller puffs before the big one. Should pose no problem except for the fact that I'm running down my two Twist 650 and mini 400 too fast. And with a 2.4/2.6 ohm head, they should last me at least 4 hours each. Do you take primer puffs? How long do your batteries last?