Brassard has dilation at once per day for 20 minutes for the second six months, and at the one-year mark it's once a week for 15 minutes for the rest of your life (which isn't so bad, relatively). Doctors' regimens vary, but most do end up recommending very brief, infrequent dilation sessions forever.
No, cis women don't have to do it. (If they did, well, what would happen with babies and little girls? It'd be closed up before any child grew up.) That's because when the body is "programmed" to have a vagina, you don't have to work to keep it open, just like nostrils don't close up but new ear piercings do. A cis vagina does collapse somewhat when not in use, but it won't heal closed. There *are* post-op women who say that they have given up dilation and their body now remembers that it should have a vagina and it's not a problem anymore; seems like that's the luck of the draw, just like some women end up self-lubricating and some don't, etc.