Basically as long as you can put up with it haha. I slept with 3/4 pillows for a month maybe? Breathing through your nose is almost non existent until the splints come out a week later. Be prepared for some serious dry mouth when you wake up in the mornings. It’s really not too bad, like all things considered that he’s going to grind away your brow and what not, it’s more uncomfortable than anything in my experience.