A question about cheetos?!
Answers:
They absorb moisture from the air and become a bit soggy. You can refresh them by microwaving them briefy at ten second intervals until the crispiness is restored. As a safeguard, roll the bag and clip it shut.
They're manufactured that way. If you have to eat them quickly before they lose the crunchiness then you will buy more again sooner. That way Cheetos makes more money from everyone.
MMMMM.... Cheetos. (Homer Simpson voice)
They don't necessarily lose their crunchiness if left outside for a few hours. If left out overnight then you have a serious problem on your hands.