Botching the SIM Card Lock
If you ruin the SIM card lock, that SIM card is pretty much useless. Until you can get the SIM card replaced, your phone will not function, and that can be a real inconvenience. If you feel the need to place a lock on the SIM card, do so VERY carefully or get help from someone who is more knowledgeable.
Exposing It to the Elements
Heat and cold can make your smart device not work properly. For example, leaving your phone in a car in the heat of summer or overnight in the cold of winter can cause issues. Although most people tend to keep their phones on them at all times, don’t leave them in very hot or cold places.