Have I told you on another occasion about that habit I have of paying for the gym the whole month and going only two days? I’m sure you will. That’s a consequence of starting out by killing yourself for results early, and burning your muscles with the 3 hrs gym effort.
Of course, on the second day you don’t want to know anything anymore! So you spoil it.
But 15 minutes a day a day doesn’t seem like much dedication required. And yet, you will be more useful 15 minutes each day, than 3 hrs in only 2 days a week. Why?
Your body gets used every day to give a little more, you let it rest enough but not too much. So day by day it gets more agile, even if it seems like little time.