I'll chime in here.
I have used dutasteride twice--
Once, for 14 months. I had to switch to generic Proscar for money reasons.
I'm on my second round now, 3 months in... But let me comment on my first trial:
Into the first 6 months, I had good regrowth and little to no shedding. When I ventured into my 6 month, I started shedding pretty badly. It isn't necessarily noticeable through photos, but I have written about it before.
After the 6-month shed, I slowly started regrowing. By Month 10, I had a lot more hair than when I started. By Month 14, I was very happy with my hair.