I go from sleeping ~3 hours a night to ~7 hours a night depending on my mood, if im feeling sad cause of all the crap in my life, i sleep around 3 hours and i walk around like a zombie not wanting to do anything, but if im feeling great i sleep 7-8 hours and im up for doing stuff outside instead of just lying around all day.
So it really varies for me, but i chose 5 as its pretty much the average.