The Lifestyle Poster
It is less a matter of "How many hours SHOULD I drum a day?" and more of "How many hours CAN I drum a day?".
Getting better should be a LIFESTYLE.
The best players are constantly drumming because the DRIVE to be the best IS ALWAYS THERE.
I could tell you to "Drum 3 hours a day and you will be amazing." But it doesn't work like that.
You have to literally drum ALL OF THE TIME.
When you wake up, between classes, after school, in-between homework, fill up your free time with getting better and that is living THE LIFESTYLE.
That will get you the results you desire.