The air is crisp, the sky is deep blue, the fall foliage is starting to emerge. Suddenly you’ve got the urge to go hiking again.

But when you dig through the closet to find your hiking gear, you realize your trusty old backpack is looking pretty threadbare and the soles of your boots are worn.

Though it may be tempting to run to the nearest discount store and buy whatever is on the shelf, or even surf for bargains on the Internet, outdoor gear experts warn that you could be making a painful mistake.

That’s because boots and backpacks have to be carefully fitted to the individual. That slight flaw or twinge that you felt when you tried on the product in the store will become magnified with each mile you walk on the trail.

Buy the right boots

Just as driving a car with bald, fraying tires will eventually cause a blowout, walking in ill-fitting boots can cause blisters or other foot problems that can bring a hike to a screeching halt.

Winton Porter can’t count the number of times he’s seen this happen. Porter owns Mountain Crossings at Walasi-Yi, an outdoors store located where the Appalachian Trail crosses U.S. 129 near Blood Mountain.

Every spring, droves of trail "through-hikers" hobble into his store, where he bandages their wounds and helps them find a boot that won’t kill them.

"People ask me all the time, ‘What’s the best shoe?’ I tell them, ‘It’s the one that fits your foot,’" he said.

Porter said it’s important to shop for boots at a store that has a knowledgeable staff. He and his employees quiz customers about their feet, asking if they’ve ever had problems such as bunions or heel spurs. They also ask what type of hiking the person plans to do, because rough terrain or a heavy pack will require a sturdier boot.

And they measure the customer’s feet, because many people don’t realize that their foot size can change with age.

Porter said he often spends 30 or 40 minutes trying to get a customer properly fitted. "Sometimes the boot itself is a good fit, but it needs to be customized with arch supports or other devices," he said. "We guarantee our fit (on boots) for two months, but we rarely have customers return them because we get it right the first time."

Daniel Jessee, outreach specialist at REI Buford near the Mall of Georgia, said his store has a 100 percent satisfaction guarantee.

"If you take a boot home and it doesn’t fit right, often we can make modifications to the boot or find a replacement if necessary," he said. "Our goal is to get people into the outdoors, and if their feet hurt, they won’t go back."

Pick the perfect pack

With boots, the need for a snug fit is obvious. But shoppers often don’t know that backpacks also should be customized for the individual.

At REI, employees use a device to measure the person’s torso, from the last vertebra in the neck to the top of the iliac crest in the pelvis.

Jessee said this measurement is more important than the pack’s overall carrying capacity, which is usually expressed in cubic inches.

"A lot of people buy a backpack that’s way too big, and then they’re tempted to fill it up with things they don’t need," he said.

Over the past decade, many hikers have jumped on the "ultralight" bandwagon, trying to cut down on their load. But Jessee said there are a lot of misconceptions about this trend.

"You can’t use an ultralight pack unless all your other gear is ultralight, too," he said. "These packs can’t carry more than 35 pounds."

Porter said customers are often obsessed with the weight of the pack itself when they should be concerned about its suspension system.

"A 2-pound pack will put most of the weight on your shoulders," he said. "A 4-pound pack can be much more supportive, putting the weight on your hips, where it should be."