Mine didn't start falling out till @ 4 months postop, I thought I was safe since I passed the 3 month mark...but NOPE! Luckily, my hair was pretty thick to start with and I always had handfuls come in the shower, now, it's like 3 handfuls, of course "handful" sounds a bit extreme, but I mean, when I rinse it out and run my hands through it, a lot of hairs come out, and any time I run my hand through it during the day, at least 10 strands come out...it's kind of scary, I think I'd be almost bald by now if my hair was thinner to begin with.
BUT....everyone is different....and I hear from everyone that it comes back....and being able to shop in regular sizes, bend over to tie shoes, wear a belt, and exercise without feeling like you're going to die (among many other non scale victories) definitely makes up for the hair that you may lose :)