It's a good habit you need to acquire. First, you get more effective sleep for the same period of time, if you go to bed and wake up at the same time every day.

Second, it's better for your health - your body will handle it more easily if you keep the same circadian rhythm. Human body gets used to your sleeping pattern, and any significant change to this pattern usually results in a stress - you can not fall asleep for a long time, or you are having really hard time to get off the bed.

Finally, when your body gets used to the schedule you've selected, it will become much easier for you to get up. You will not even need an alarm clock.