At 3am she will not look at her feet. She will sit on the edge of the bed, reach for whatever is nearby, and stand. Whatever is on her feet at that moment either holds the floor or it does not. That is the fit you are sizing for, not the fit that felt fine in the store at noon.

Local option: New Plan Care gives families in the St. Louis area in-home help so a parent can stay home: companionship, help with bathing and dressing, meals, and overnight care. Call (314) 405-0887.

Before you go

Go at the time of day she is steadiest, and keep in mind that feet and ankles are often at their fullest later in the day. Bring the socks she wears to bed, because a thick sock changes the fit more than most people expect. Bring the route written down: bed, door, hall, bathroom, and the floor surface in each room (carpet, tile, wood, a rug edge).

What to check on the shoe

Check the heel counter first. Press the back of the shoe between your thumbs. If it folds or collapses, her heel will tip inside it on the first stand, so choose a firmer back. An open back or a backless slide gives her no hold at the heel, so pick a closed back with a strap or a sturdy elastic panel.

Check the sole next. Look for a flat rubber-type tread across the whole bottom, not smooth leather or slick plastic. Turn it over and look at the tread under the ball of the foot. A worn tread grips no better than a smooth one, so plan to look at it again each month.

Check the heel height. Low and flat is safer for a night walk than a raised heel, because a raised heel shifts her weight forward as she takes the first step off the bed.

Check the width across the ball of the foot. The sole should lie flat under the widest part of her foot, with no pinch at the sides. A shoe that pinches pushes her toes up, and that changes how she lifts her feet on the walk.

Check the fastening. Hook-and-loop straps let her adjust for swelling and let anyone helping her set the fit quickly. Laces can loosen or catch on the walk, so if she uses them, tie them once, check the knot each night, and keep the ends tucked.

Test it on the route

Have her stand. Walk the whole night trip in the shoes: sit on the bed edge, stand, walk to the door, down the hall, into the bathroom, and back to the bed. Do it three times. Note where the shoe slides on the floor, where the heel lifts, and where she has to look down to see where her foot is going. Test on the floor she has at night, not the store floor. The bathroom threshold is often the slickest spot when a rug is damp, so give that spot extra attention.

What to write down

Write the brand, size, and width of the pair that fit. Note the time of day you tested, what the heel did, what the sole did on tile, and which fastening she chose. Keep the receipt or box with the pair so the return window is easy to find. Keep one pair by the bed, in the same place every night, and keep any spare in the same spot as the first.

When to stop and ask

If her feet hurt, go numb, show redness or sores, or the swelling changes from day to day, that question goes to her doctor before it goes to the shoe store. A fitter can tell you what fits the foot you have today. Only her doctor can tell you why the foot is changing.

For the order of the whole night plan, see Start here: a reading path.