The idea of holing myself up for an intensive day's writing used to make sense to me, but - as with so many things that I took to be the bread and butter of a writer's life - I've discovered that it's a waste of time. On days like that I would sometimes write a few more words than normal, but they'd be crap words and would always end up being deleted. I'd also finish those sorts of days feeling shaky and dizzy and would struggle to string a sentence together. My brain is not designed to generate non-stop creative content, and I doubt anyone else's is either.
Nowadays, I'm, all about breaks. Taken outdoors.
Taking time to get outdoors somehow creates a whole load more writing time. I haven't a clue how or why this works, but it does. (It is also the best way I know to solve plot problems.)
I'll go for a walk; a run; a cycle up the nearest hill. Even if I've got a cold, and it's winter, and I want to rot in my fuggy, germ-filled bed, I take a chair and a blanket outside and I'll sit, watching the birds, smelling the air, feeling like a human in the world, as opposed to a mad writer in a room.
Take a dog; don't take a dog. Go rural, go urban. Just get out of your house and get moving.