How much you use it and what voltage you use will effect that. Even the non-NiCad batteries have only a certain number of times you can charge them. Good charging habbits are Charging them only when they are all the way down, Fully charging them and remove them from the charger. If you only let them go down part of the way an stick them in the charger you will use up one of those charges and not get the length of time out of them. So I plan on running mine dead before charging. While these batteries are not suppose to develop a memory (caused by charging them when they are not all the way down) they still have only so many times you can charge them. Heat will effect them. Don't leave them in a hot car. When I get a spare I will store it in the Refrigerator.
Other factors will be keeping the contacts clean as that will effect both charging and vaping.
Personally I am going to get a Provari for my second battery. On them you can change out the battery in the unit and exchange it with spares that can be charged out of the battery backage. When the battery dies you can put it in the recycle and buy a new one for a fraction of the cost of replacing a Twist. Plus with the Provari you get more voltage choices and a cheaper and smaller spares.