A few recommendations.
Never carry Battery in pants pocket with any 510 threaded device attached.
Never tighten any 510 device on the battery
Both these things chew the threading away on Ego style (almost all)Batteries. Joyetech are least susceptible to wear.
Devices - Snug to contact and stop - never twist to tight.
Batteries - always keep at least 1 backup and better to have 2 batteries in rotation and a couple of backups. These can be had for less than the cost of one Carton of smokes and are a much better investment.