so how about this: when you earn experience points, you don't get them right away. the DM will write down the experience that you've earned, and you get to wite them down when you get a good rest. how much you get to keep depends on how good of a rest it is.
because I'm not an asshole, the default is '100% of your experience.' you get to keep what you earned. those goblins are dead and you killed them and you learned how to be better at inflicting violence. keep up the good work. it doesn't matter if you spent your time sleeping in a monsoon under that flimsy tent you wrote on your character sheet when you made the character and that you've apparently been carrying with you while you were being beaten up by ogres and catching arrows with your torso. it still counts. one of the functions of sleep is to help encode your memories and I guarantee you will remember a good chunk of what it is to be scourged by some nightmare acid in two weeks's time.
but treating sleep and rest like it literally doesn't matter is kind of... odd, isn't it? in real life, you spend like, a third of your day sleeping. you have a whole room in your house dedicated to the art of the snooze. probably. if you ask a hundred real life American human beings if they wouldn't mind trading their warm bed with air conditioning for a night on the streets with just the clothes on their backs, I bet you wouldn't get a single one without offering them something in return. but in fantasy games, I've had my players weigh whether they want to pay the innkeeper a handful of their hard-earned loot or if they'd rather just sleep outside of the city in their tents because, who cares? what difference does it make anyways? we'll set a watch.
in this world, a soft feather quilt is exactly as good as a threadbare woolen blanket. a king's bed is just as good as a quick snooze on an ooze-slick dungeon floor, or sleeping in a barn. a campfire is where they'll cook food, assuming that they've bothered to bring anything that isn't abstracted to 'rations,' and even then, it's not necessary that they care in the least. rations are rations, you have to eat one because the dungeon master says it's time to mark one off your character sheet, and that's it. let's get back to the parts where it matters, eh?
