Yeah same mate, I started off using one bottle every 45 days or something, now its down to every 15 and I can't make them last any longer! I've taken to using the liquid at night so I'm not using far too much every day, and its cheaper too.
I use one per month and also apply to my entire scalp including hairline and am having good results from it. Using any more than 1 can every month/month and a half is a waste.
ALL depends on how much you are losing.. ie... how much of your scalp you are losing, in temples only? in the vertex only? in the entire horseshoe pattern? How big your friggin head is? Once or twice per day apps? Its not an exact science so everyone should be different I know the bottle says only the back of the head is effective but we all know this is not at all true (fortunately.)
sucks cause its kinda a b**ch to apply or just pretty much takes a lot of time to do with all the parting and stuff so i shaved it until i get most of my hair back then i m gonna grow it out again, i just have a receding hair line which alot of people say it hard to regrow