I found this question. One of the answer tell the flaps are generally retracted after landing. I assume this mean flaps are retracted when the airplane is on the ground between flights.
Flaps are extended for landing and then extended again for take off. Not taking care of their position while on ground (no need of them) and putting them in the required position before take off may save (few) flaps actions (something like putting them from landing to take-off position instead of landing position to fully retracted and then from retracted to take-off position).
Is there some good reason to retract the flaps on ground? Does this good reason varies from a type of aircraft to another?