Asking for a friend.
If you’re getting bed sores, you might want to at least change position.
With or without a cat?
Because if I’m in bed, and want to get up, but the cat is using me, the cat says that it’s too soon if they aren’t done sleeping on/near me.
No such thing as “too long” if you have a tablet with both stored movies and TV shows and access to streaming content and the internet in general, plus a Kindle, plus a headboard that is actually a bookshelf loaded with physical books, plus a side table loaded with more books.
Getting in and out of bed is a lot like getting in and out of a pool. Either in or out is fine, but the transition is annoying.
Right there in the very first reply by Dewey Finn. Asked and answered.
With my new mattress, the answer apparently is “Never.” It sustains and nourishes me. It is life, it is joy, it is eternal.
The responsibilities of my life say otherwise, however. They say “Eight hours, tops.”
Mister and Owner Madigan, in the Cordwainer Smith SF book slept for tens of years at a time, just waking up for a few hours to check on things now and again.
Of course he had robots to keep things properly under control in the meantime…
Wake me up in 50 years or so…
Wake me up before you go.
I’m idly curious what prompted the O.P.
Personal best guess is it involves a teenager in some way, and also that the word “lazy” and possibly the phrase “good for nuthin’!” came up.
May wanna add “bedpan” or “diapers” to that list, if you’re really gonna commit.
This is profoundly true.
I wonder if John and Yoko weren’t right?
I kinda live in my bed.
If not for Ivy prodding me out on far too many occasions, I think I’d be in there permanently, except for bathroom and pet needs.
I’m tryin’ folks.
With help.
Where’s my poster paper and markers. I want “Bed Peace” “Hair Peace” would be nice, too!
With the right bedmate it might be only as needed to eat & poop, so briefly maybe once every 3 days?
When either rigor mortis or decomp starts setting in.
Longer than your bladder can manage to hold urine is too long.
Longer than your dog’s bladder can manage to hold is also too long.
Long enough for both your cat’s belly and their food dish to be empty is too long.
Long enough for your muscles to atrophy and/or for (as has been mentioned) bedsores to set in would also be too long; but one or more of the first three is likely to happen first.
Treating bedsores can be a challenge. But it can be done.
I think this thread has much in common with the one that discusses mind uploading. The annoying problems of eating, peeing, and pooping go away once you upload your entire being into a silicon chip. Then the silicon chip – with the appropriate sensors for appreciating the nice warm bed – can stay there forever.
Of course, a philosophical debate may be had about how this is different than death.
It’s possible that this thread about lying around in bed may have morphed into unintended and perhaps rather morbid directions. 
Yeah. Nothing good about a Chip Shit.
BRAIN: Sometimes I wonder why I even bother getting up in the morning.
PINKY: To…avoid bedsores?
If that’s the case, it’s a shame, as teenagers need more sleep (says the guy who got shit for sleeping in as a kid: “he awoke at the crack of noon” my mon used to say)
You’re in good company.
Much like Major Major Major Major’s father:
On long winter evenings he remained indoors and did not mend harness, and he sprang out of bed at the crack of noon every day just to make certain that the chores would not be done.
I don’t eat a whole lot, but … even my scrawny ass would starve on those rations.