As far as age I don't really think it makes any difference as I have seen patients from 20 to 65 on different Dr.'s websites.
In my case I have had three procedures done at age 41, 44, and 45. If I look back on old photo's from age 30-35 I had a lot of hair, relatively speaking. From 35-40 I started losing a lot in the crown and had a 2 1/2" to 3" bald spot by age 40 but still a pretty good amount towards the front. The crown area was filled in at age 40, to a satisfactory degree but between age 40 and 44 the frontal area started to go quite fast. In my case, with each procedure I was bact at work on the following Monday and since I wear a baseball cap at lot any way nobody noticed or questioned a thing. After all the new grafts fall out in a few weeks it just looks like you have a sunburn in the grafted area. The scar can be covered over by letting your hair grow long in the back before the the surgery. Only my wife and kids, a couple of close friends and of couse my hair stylist know I have had this done. If any has montioned anything about my hair at all, it was to say, "oh you are letting your hair grow out now" or that I am wearing it different or something. It is totally natural looking and grows in so gradually over the course of a year that no one can remember what you looked like a year ago with your thinning hair.