After practically living on them for 36 hours as Hurricane Harvey flooding threatened her Katy home, Sheryl Davis jokes she'll never eat a granola bar again.

"Oh, we got so sick of them," Davis, 33, said of her and her six-year-old son Bruno. "Next time, I'm not going to wait to go to the store."

While she was lucky - her home never flooded and she lost power for maybe an hour - Harvey did teach her that a little preparation can go a long way.

Harvey's waters have receded, but concerns about the next major storm or disaster remain, prompting many to take stock of their stockpiles of food and other items.

Sporting goods and hardware stores are reporting increased sales and interest in on solar power generation, batteries and water filtration, as many people try to prepare for what they recognize is an eventuality in Houston: Living without aid for a few days.

Even some items at grocery stores are doing brisk sales after the waters have receded. HEB carries five kinds of powdered milk and typically sold about 500 units per week in the Houston area, grocery spokeswoman Cyndy Garza Roberts said.

"The week the storm hit and the week prior we averaged 2,000 units sales a week," she said.

Even as the intense recovery sales have ebbed, HEB still is selling about 600 units a week, though the increase could stem from various factors, including people still living in limited conditions as they rebuild homes.

Interest in increasing readiness varies from the casual newcomer who just needs to charge a phone to the all-in prepper who wants to be ready when stores become war zones, water and fuel is scarce and anarchy sets in. Many on the extreme end point to how Americans jostle and joust for discounted televisions. Imagine, they say, how people will act when - not if- Houston starts running out of food.

A dozen people, from the curious to the concerned, gathered at an REI store in Baybrook earlier this month for a 90-minute lesson on urban preparedness. The classes, a fixture of REI's outreach to customers of the sporting goods co-op, teach tips and tricks for emergency planning along with suggestions of supplies - including items offered at the retailer. Most follow a pattern of preparation and situational awareness, covered quickly in 90 minutes.

Only Mike Feaster's welcome to the most recent class was new.

"Did everybody make it out of the storm OK?" Feaster asked.

No one is exempt

Harvey loomed large in the classroom. Long-time emergency preppers said they wanted to refresh their skills and focus on protecting their pets in future storms. One woman, a newcomer to the area, said she just wanted to be able to take care of herself in a heavy storm.

Feaster, an avid hiker and former soldier, returned numerous times to the need for everyone to have a plan and a way out.

"You are not exempt from disaster," he told the class.

He knows from first-hand experience. His Dickinson home flooded. He and his family escaped via canoe.

"We evacuated for Ike and the one before that," Feaster said. "What's that called, Murphy's Law, when what can go wrong does go wrong?"

When a lot can go wrong, emergency management officials encourage people to be ready.

"I think we have a long way to go to create a true culture of preparedness within our citizenry in America," Federal Emergency Management Agency Director Brock Long told CBS News on Sept. 11, as Hurricane Irma whipped the Florida coast. "We have a long way to go to get people to understand the hazards based on where they dwell."

Harvey helped reinforce that with many people, if only for minor changes. Renewed interest in readiness has led to an uptick in sales of certain items, workers at sporting goods and hardware stores said.

"What I've seen is a lot of questions about solar power and filtration," said Eric Brown, manager of the Baybrook REI. "They want to be ready for the next time."

People also are stocking up on those core items for emergency kits.

"Categories related to preparedness items - first aid, lighting, etc., - have seen an increase in sales post Harvey," said Allan Rojas, spokesman for Katy-based Academy Sports & Outdoors.

Taste and test

While many in the Houston area never lost power or were powerless for a few hours, the threat of a major outage always looms. Residents who endured Ike remember days without power, which impacted everything from buying fuel to moving around at night.

Brown said many people simply are aiming for a small backup.

"They're saying 'I just want to keep my phone charged,' " he said.

Chuck Beard, 44, decided to go bigger. Last week Beard used his lunch break to shop for gas-powered generators at the Lowe's and Home Depot locations along Loop 610 near Ella. Though he never lost power during Harvey, Beard said listening to his neighbors recall Ike made him nervous about losing power for an extended period.

"It's just another thing I'd rather have, for safety," he explained.

Having the gear is only part of being prepared, Feaster urged his REI class.

"You've got to have a positive mental attitude," he said, adding that panic or losing perseverance can be devastating.

One way to ward that off is being ready and aware of what to expect. People often stock up on nonperishable food, then are stuck with something horrendous.

"Make sure you have something you like," Feaster said. "Do not go without trying it."

The same try-it-before-you-need it philosophy is needed for equipment, as well.

"Everything you do, test," he said. "Test your map and compass skills."