If not in use and if the battery is connected to some kind of atomizer, I do the 5-click disable just in case it gets pinned against something and the button is continuously held down (say if
thrown into a backpack or something). Although most
devices have a time limited shut-off period, so it probably wouldn't cause a fire, but it sure would not be the best situation.
If the battery isn't connected to anything, it's probably still good practice to 5-click disable if the battery is loose with other items inside a pack or something. Cause worse than a atomizer burning up, is the battery shorting on a piece of metal... li-ion batts and shorts do not mix very well!