1 solar day is how long it takes between "high noon" (meridian transit) on two consecutive days.

1 sidereal day is about 4 minutes shorter and the time it takes for the stars to be in the same position.

As far as I know, unless you're doing certain types of astronomy, you're using solar days.

You also need sidereal days for computing the Coriolis parameter, and both oceanographers and meteorologists need to know that. So the astronomers are in good company (or bad, depending on your point of view).