How long after starting propecia without hair loss would you be considered as stable?

[renordw]

I have been on propecia since I was 20 years old, and today I am pushing 28. I was emotionally devastated when I lost my hair so young but since then my hair pattern has been very stable. For me, my (natual) hair line is exactly where it was back then; minus my transplants. I have not ever missed a single dose.

I am wondering, if you are not losing any hair, how long would one have to maintain a pattern to be considered as stable? Or in another question, how old would you have to be to be considered as stable?

The reason I'm asking is because so many doctors are unwilling to implant too much density because of fear of future hair loss.