Do you know how long cats usually sleep for at once? Google won't tell me.
I mean...cats definitely sleep a lot. Something like 15 hours a day or something--I don't recall exactly but it's a lot. I've seen my cats sprawled out in a particular spot and they'll often still be there hours later. I think it depends on the cat.
That said, if you have a cat that you are struggling to rouse, that seems excessively lethargic, or that won't wake up at all, you definitely should make sure the cat's okay. When cats do hit their deep sleep they pretty much will sleep through anything but I find mine are rarely that deeply asleep for more than an hour or two at a time.
Also age is a factor. Kittens need a LOT of sleep (because they're babies) and they tend to conk out and stay out even if you man handle them, which can be really super cute. But adult cats tend more toward light dozes most of the time. Again, in my experience.

















