There are certainly many variables. One is the length of the hill. Short hills you might sit through them, or do the whole hill standing. I've done rides with single climbs of 4000-5000' and total climbing of 12000'. On the longer climbs I change things up, sitting, standing, varying cadence, pedaling with heels up, heels dropped, etc. to vary how the muscles are used.

Generally lighter weight riders will tend to stand more than heavier riders.