In many homes, having a sump pump is a necessity. It could be that they live in a low area that has a lot of water accumulation, or on a flat area where the groundwater level is fairly high. A sump pump will keep you from getting a flooded basement in these situations. It is a simple mechanism, but maintaining it will save you from the risk of having it fail when it is needed the most.
So what can go wrong with a sump pump? Well, one possible issue is that the float that turns the pump on and off when water enters the trench where it is located could get stuck to the side of the trench when not in use for a longer period of time. If you know a rainstorm is coming, it might be a good idea to pour some water into the trench to make sure that it activates the pump as it should.
It is also a good idea to have a backup power source for the pump, especially if you tend to lose power when there is a storm. That way you won’t wake up to a flooded basement when you thought you were safe.