I don't everyday. If I do need to get up at a specific time, I'll set my phone alarm, just to be safe. A lot of the time, I too, will wake up before he alarm goes off.
Funny thing, I always wake up 15 minutes before the alarm. I have my mobile phone set-but why? Also, it is bizarre if I have to get up very early, I will wake up at the exact time even though I set the alarm.