it's not always just the ohm, many times it is the quality of the Atty or Carto's build that also counts, I run mostly all HH-357 Atty's and have 5 going on 5 different Mods now for over 5 months and they run as good as new. I recommend you try one of these, they are worth the $21 simply for how well they perform because of how they are built, plus you wont find to many Atty/Cartos that last for this amount of time, plus the flavor you get from them is really super. There is a small Break in period maybe 30 vapes or more then there golden ripe ready to go for a long time, keep them very very wet. They sell them from 1.5ohm up to 3ohm but the 1.5's are really super on a 3.7 Batt. Available at Avidvapor.com