I have enough mods on the go at all times that I alternate, plus I charge them as needed, usually overnight.
If one mod is low and I want to keep going, I switch with my spare set on the charger, but the one mod that does not have charging (SMOK Xcube2) tries to eat the wraps every time I take the batteries in and out... I have no clue to what the heck they were thinking with those massive springs.
Basically the batteries are at their most vulnerable when out of the mods.. many rip the wraps during the taking in and out of the mods and the chargers, and I can attest to that.
And in case someone starts the whole "mod doesn't charge right".. with a decent mod, that's absolutely false and just old mentality for the much older mods that aren't close to what we have now.