I agree with DressageBelle as I do practically the same thing at my stable. I arrive for my Saturday lesson about 1 1/2 hours before my lesson to clean and tack. I then stay about 2 hours afterwards to clean and tack again.
I go back out on Sunday for a good 3 hours to clean, muck, trash etc. I certainly don't have to do it, but it allows me to be around the horses more.
I see it as a gift to myself.
My only advice would be to make a commitment and really try to stick to it. You will all be rewarded in one way or another.