The next time you lace up for a walk, ask yourself: How old are these shoes?

What you wear — and how worn out your shoes are — makes all the difference when it comes to back, foot and ankle problems that often require orthopedic care.

The most common injury risks? Plantar fasciitis — which causes heel pain — as well as stress fractures and knee and lower back pain, often caused by worn soles and lack of shock absorption.

Depending on how active you are, if it’s been about a year since you bought new exercise shoes, it’s probably time to invest in a new pair, said orthopedic surgeon Dr. Seth Richman of Novant Health Orthopedics & Sports Medicine - Cornelius.

Here, Richman discusses what to look for and what to avoid when lacing up, whether you’re someone who takes casual strolls around the neighborhood, or logs miles on walking trails.

When patients complain of pain from walking or running, do they typically suspect their shoes are the source?

Not always. Sometimes people don’t realize their shoes are the issue until I point out that they’re falling apart. You can’t wear the same shoes for years at a time. If you’ve put more than 500 miles on a pair of walking shoes (or 400 miles on running shoes), that foam is done and the tread is worn out, which can lead to foot and ankle problems. Flip your shoe over and look at the bottom; if the rubber is worn out significantly in one area, it’s time for a new pair.

Do I need to buy expensive shoes or customized inserts if my goal is to walk daily?

Not necessarily. For the average person without a significant foot abnormality — including flat feet, high arches or past fractures or surgery — you’re better off going to a specialized running-shoe store with knowledgeable employees.

But avoid retailers whose business centers on high-priced specialized arch-support systems and inserts rather than a broad inventory of footwear. These stores sell you over-the-counter plastic and foam that sometimes costs more than $1,000. Instead, I send patients who need inserts to a professional orthotist who can customize an insert for about $400.

How should a pair of walking shoes fit?

They should not be tight. Go up a half-size from your dress-shoe size, because your foot naturally swells after walking for a while. And make sure your toes don’t rub inside the shoe.

What are zero-drop shoes?

Zero-drop means the foot and the heel are at the same height, instead of your heel being slightly elevated. This loads the Achilles tendon and the forefoot a bit more, and there’s not as much arch support. Switching from a basic Nike to a zero-drop shoe will dramatically change the way your muscles feel, specifically the calf and your Achilles. They can be good for a natural stride and better posture, as well as strengthening the lower leg and foot muscles, but they take getting used to.

What do you think about other footwear trends, such as highly cushioned shoes versus minimalist athletic shoes?

Trends are fleeting and trying to sell you something. Take max-cushioned shoes: Avoid them if you have a balance problem, because you’re going to tip over — you won’t feel the ground anymore. You have to know your body and customize accordingly.

Does body weight affect wear and tear on shoes?

Weight definitely plays a role. Unfortunately, nearly half of North and South Carolina residents are living with obesity. The heavier you are, the more force you’re putting through your shoe, and the quicker it’s going to wear out. But for every pound you lose, that’s 5 fewer pounds of force, which adds up quickly.

I feel like I'm replacing my walking shoes more often than I used to. Is that normal?

Yes. Exercise shoes are not designed to last forever. Over time, the cushioning and support materials compress and become less effective, even if the shoes still look fine on the outside. Some brands seem to wear out more quickly than others. In my experience, Under Armour and HOKA tend to have a shorter lifespan than others.

Do I need different shoes when walking on a treadmill versus a sidewalk or a trail?

Yes. For outdoor activity on uneven terrain, you need a shoe with good tread and grip for proper balance. Carbon-plated shoes (which combine a stiff carbon-fiber plate with thick foam) allow for better push-off, and stability sneakers feature a thicker and stiffer midsole with side rails to prevent rolling your ankle.

But on a treadmill or a sidewalk, this isn’t as critical. Be aware that one of the simplest but most important things you can do to prevent injury is to lace up properly. That means to pull the laces tight enough that your foot doesn’t slide forward or lift when you step, but not so tight that the top of your foot hurts or feels numb.