Today I woke up 15 minutes earlier to the alarm. I set my alarm to 4:45 deliberately and went to bed at the exact time I used to go before 2 years. Today morning was my only 4th day of doing it, I naturally woke up at 4:30. Let's see if I can wake up regularly...or it's just a fluke, though I nearly woke up everyday at 4:30 for 20 years or so.