Great question! Small satellites are generally expected to last from 3 to 5 years. Larger ones can last for over 15 years. Satellites also lose their height every orbit by a very small amount, so they need to be corrected regularly to stay in the same orbit. Sometimes the life of a satellite is determined by how much fuel it can carry to keep correcting the orbit, once that fuel is over, the satellite will come back down by itself, and burn up in the atmosphere.