i put atty o 3.7 for a dry burn and it diedmy 510 atties last months and months at a time...
about every other week or so the vapor drops off a bit because I vape mainly tobacco and or dark colored juice (so the atty gunks up faster)...
to remedy that I blow out the atty, put the atty on a true 3.7V device and do a complete dry burn and it's back to tip top shape...
look up the user highping and his atty resurection method...I just follow an althered version of that..