and very little damage from masts left up.
Every year someone damages a tang or spreader in storage, or raising lowering and the mast, and it has to be fixed. A number of times the damage wasn't noticed and the tang failed bringing the mast down while sailing.
Never mind the stuff dropped overboard or busted antennas and birds.
What "stresses" outside of acceptable loads would one expect leaving the mast up? Assume a well built and well maintained sailboat, not a POS.