There’s a reason we have a saying that refers to “happy campers.”

As in, if someone’s cranky, they’re “not a happy camper.”

Blame their bag.

One of the real keys to enjoying multiple, consecutive days outdoors is getting a good night’s rest. No matter their enthusiasm level going into an adventure, the person who goes one or more nights without getting proper rest is going to eventually run out of steam and, in the end, not have any fun.

Having the right sleeping bag can hold all that at bay.

But which is the right one?

That depends on several factors.

One is the season. That $200 mummy bag, good for 10 below zero, might be the best bag on earth for winter. But tuck someone in it on an August night and you can expect sweaty rebellion.

Bags are rated by the temperature in which they are meant to be used. A summer bag, for example, might be good for keeping you warm when nighttime temperatures drop to 50 degrees. A three-season bag might be good for 30 degrees, a winter bag for zero or lower.

Pick the bag appropriate for the weather you’ll encounter.

Next, think of shape.

Do you like to be able to squirm at night? If so, a roomy rectangular bag might be the way to go.

If you don’t mind rolling over in tandem with your bag instead of inside of it, a mummy bag – designed to offer maximum warmth while still weighing as little as possible – is the better choice.

You can always go with a tandem bag, of course, if you want to sleep with your partner in a tent the same way you do at home.

Consider insulation, too.

Some bags are stuffed with down. It provides a lot of warmth relative to its weight, compresses well without losing its fluff over time, and is light.

But get it weight and it largely loses its ability to insulate. Down bags can be pricey, too.

Those stuffed with synthetics tend to be less expensive. They work even when damp and dry fest.

But they can be bulky, too.

Finally, think of extras.

Does your bag have a hood, something important in cold weather? Is it big enough? Regular bags are good for those up to 6 feet or so; extra longs are for those who are taller. What about the zipper? Does it have anything that makes it snag proof? No bags are foolproof that way, but some have more thought put into their zippers than others. Does the bag come with a stuff sack or will you have to buy that separately?

Buying the right sleeping bag isn’t overly tricky. But there are some questions to ask and answer before you plop down any money.

Keep a few things in mind and then you’ll be ready for an overnighter of fun.

More from Everybody Adventures

See also: Sleeping well in a tent is possible.