For how many years you left your baldness without treatment, and even after those years you managed to see regrowth

I am wondering what is here the longest record for someone that left his head bald or just hairline for several years and still managed to get good results. I am asking this question because we all know that you have limited time to regrow your hair, because if Left untreated the hair follicle will be dead forever. I read multiple studies you have only from 1 year to maybe maybe at the best 2-3 yrs but rarely. Is there some guys that managed to see results even after those years