Will you be using disposable or cloth diapers? Diaper pails with narrow openings and special liners aren't the best choice for cloth diapers. You may find you can't fit a bulky cloth diaper through the opening, and if you do, you may be cutting the diaper out of a plastic liner only to throw it in the washer. Look for a simple, easily opened pail that can accommodate a waterproof bag that you remove for quick trips to the laundry room.
Do you mind buying special refill bags? Many diaper pails require proprietary liners. If you hate the thought of shelling out more money, look for a model that is compatible with standard trash bags.
How often do you take your trash out? If you don't want to empty the diaper pail and take out the trash every couple of days, choose a model with a higher capacity and adequate odor control to save you the hassle.
Are you a germaphobe? Some pails are more "hands on" than others. Look for a hands-free model that will minimize contact with dirty diapers.
Does design matter to you? Most diaper pails are white hunks of plastic with a utilitarian vibe. While stainless-steel diaper pails are easier on the eyes, they're harder on the wallet.
Many diaper pails are inexpensive, but special liners or bags boost your bottom line. Buying the liners in bulk is one way to save. Be sure to comparison shop -- you may find a better deal online than at big-box or baby retailers. Other diaper pails are compatible with standard trash bags, so consider whether a more expensive pail that can use trash bags might be cheaper in the long run. One more potential money-saver: Some diaper pails can become trash cans after your child's diaper days are over, and wet bags can become standard laundry bags, gym bags or beach bags.