Well if they are doing their doctor i think they should have knowledge about time management and what they have to do to reach their goal. Depends on the major they are doing their doctor. There are social or philosophical doctors where you can waste your time but i made my master in a room full of other engineer doctors and no one had the time to waste their time on facebook or anything else. We were in the laboratory or programming our simulations or writing about our works all the time and i mean really the whole working day.