I'm 5 1/2 years post and my maintenance dose is 10 mgs. We are trying to lower it one MG at a time. It's actually on my list of things to talk about with my transplant doctor today.
It really depends on your history. Every time I tried to lower it in the past, I would get a cold or something else would happen that I needed a bump. It just all depends on the individual patients/circumstance. And I'm only 4'11" and 108 lbs so I don't think size has much of a correlation with dose.