The types of stories told in Doctor Who usually happen quickly, one event after another. For instance The Unicorn and the Wasp seems to happen in one afternoon running into the evening.
These stories rarely show anything happening over days where the characters are asleep.
Do Timelords sleep? Do they need to, or is it a choice? Is there anything that brings up whether they need sleep or how often they need to eat or just what their needs are to survive physically?
And, on the sleep issue, I don't mean in something like Family of Blood, where the Doctor has changed himself into a human, or in situations like right after a regeneration where a Timelord may need time to deal with the regeneration. I mean in general, as in day-to-day living when not under extreme conditions.