If you plan to go hiking with your dog, you’ll need to think about your pooch’s gear as well as your own. That begins with your dog’s backpack.

For starters, the size is based on the measurement of the fullest part of your dog’s rib cage. Once you fit the pack on your pooch, snug up the straps so it won’t slip or rub. But don’t make it so tight that it interferes with breathing.

When the pack fits just so, let your dog get the feel of it by wearing it at home and then trying it on walks. Once that’s second nature, add a few pounds, balancing the weight on both sides. Then gradually—and symmetrically—increase the load until your dog can carry about 25 percent of his own weight. That may vary based on your buddy’s size, strength and age, so check with your veterinarian before heading out on your hike.