Just because you can sleep longer doesn't mean it's "good" for you.
Sleeping too much can be bad.
For example, usually after eight or nine hours, I wake up, but I'm usually so sleepy I'll drift back off for another few hours unless I need to get up for work.
It's all about routine though man, without me over complicating things.
If you go to bed at 11 every night for two weeks and get a good 8/9 hours sleep, you'll get in to a good routine and wake up every morning at the right time feeling reasonably refreshed.