Ok, all of those devices have their own built in protection.
They all shut the
device down at a low limit, to prevent the battery voltage from going too low and damaging the battery. When your spinner or eGo turns itself off the battery isn't completely dead, it's actually turning itself off when the battery voltage has dropped to 3.2 volts. MVP will do the same thing. Running any of those until they turn themselves off it perfectly fine. In other words, they know what they are doing. It's the mechanical mods that have no circuitry at all in the PV where you have to start worrying about draining
batteries too low.
On the other end, a partial charge doesn't hurt a Li-On battery either. It will most likely be the exception rather than the rule that you don't have time to do a complete charge, but it won't damage the battery or shorten it's overall life span. But the shorter run time due to a partial charge might annoy the bejeezers out of you.
