Why don't people on Tatooine wear shorts? They normally wear low-cut shirts with pants. Wouldn't you think that they would wear shorts instead of full-length pants? There are several reasons to wear shorts
1) Ventilation
2) Less hot when on a desert
3) It doesn't make sense to wear pants in such a hot environment

Reasons to wear pants
1) Protect legs from sandstorms, rocks, etc
That's really the only good thing about wearing pants.
When there are more reasons to wear shorts, why go with pants?