Whether you’re just starting a walking program or you’ve got your exercise routine down, the proper pair of walking shoes is essential. And getting the right fit is the most important factor in choosing the right walking shoe, says Arnold Ravick, a podiatrist at Capital Podiatry Associates in Washington, D.C. and an American Podiatric Medical Association (APMA) member.

The right shoe should be roomy enough to minimize rubbing against joint deformities, such as bunions and hammertoes, which can cause corns and calluses, but also be snug and firm enough to provide sufficient support. Ravick recommends a cross-trainer as opposed to a running shoe. “It’s a little heavier, but it’s sturdier,” explains Ravick, “and works well for walking and moderate exercise.”

When trying on shoes, move your foot to the front of the shoe and insert your index finger into the shoe behind your heel. If your index finger fits, the shoe fits, says Ravick. The width of the toe box is very important, especially for those with deformities in their toes. As your foot and toes swell, a tight toe box can aggravate bunions and cause additional painful problems.

The time of day you shop for shoes can make a difference. Shop when your foot is swollen and feels the worst to get the best fit, says Ravick. “If your foot can tolerate a shoe when it feels bad, think how great it will be when your foot feels better.”