Refer to the Rogaine thread which has around 650 pages of posts.
1. Gains sometimes remain, and sometimes they don't . This is entirely unpredictable.
2. Never used the stuff, but know the potential side effects of starting Minoxidil and don't do it until you are atleast over 25.. Because there is plenty of time for development. I am going to be 27 soon , and i have never had much growth, i am only now try to grow something , but even the density is nowhere near " normal" . I have a fair bit of Vellus , so i know one day i will have alot better coverage, but have no idea when Genetics)... I used to care alot more, now i have learned to live with it.