Like @anon13011326 advised, the consensus is to let them run down…BUT …
it depends on the device you have them in.
For example, an early mech mod, a straight-pole flashlight, etc…probably
will not have the [electronics] to keep it from a total discharge, which would NOT
be good, whereas [most] modern devices have electronics that will cut the current off
at a safe discharge level…make sense?
Take time and [google] Mooch and ALL of his recommendations on batteries, and
there are some here on ELR. Most of his reviews are in easy layman’s terms too.
You are rightly commended to even ask such a question, kudos mate. Best safe, not sorry, eh?
Your VT Inbox will stop firing when the batteries reach a safe discharge level, maybe
around 48% or somewhere thereabout . Safety is built in, and for good reason…
not so much in the early vape days when the main rules were cast to the wind.
Not to say there are not rules of safety still to adhere to today, as there are some
strict ones, i.e. battery wrap condition, battery carrying practices, ohms law, as a few…
But for the most part, mods have been implemented with wonderful safety features,
to protect our asses from ourselves…so to speak, eh?
So chuff in faith that you are safe…and economical per your batts.
BTW, never…never buy cheap-ass batteries…they always cost more.
Again, check Mooch’s recommendations, then shop for price.
God bless you and loved ones.