They both never stop "working". The mechanism of action for minoxidil is to stimulate growth. As long as you keep using it, it will do that. The mechanism of action of finasteride is to block DHT. As long as you keep using it, it will do that. However, if your genes are programmed to aggressively make you go bald, your genes will always win the battle. If these medication were cures, we would never go bald. There is not a single person in this forum that can accurately predict exactly how much hair they will lose in a lifetime. You can estimate based on your pattern but you don't know for sure. Many of us who started early on treatments cannot predict for certain if we did nothing, we would have still been the same. I started early and maybe if I did absolutely nothing after over 15 years on finasteride and minoxidil, maybe I would be exactly where I am now. I obviously don't have aggressive male pattern baldness since I mostly maintained. There is no way I can prove if my meds did it or I was never meant to be bald. I have the gene. I was tested for it. So I know that much. We all take these meds like an insurance policy. I said this before.