Amazing advances in materials and electronics have turned the wheelchair into a state-of-the-art vehicle that can incorporate more gadgets and gizmos than you'd ever imagine. And the good news for wheelchair users is that the new chariots are far more versatile, durable and easy to take care of than ever before.

The standard big-wheeled, sling-seated, one-style-fits-all chair has become a Model T when compared with today's lightweight engineering marvels of mobility and adaptability. Solid-state construction, automatic pressure-relieving cushions, computerized sensors that automatically change the chair's settings depending on the type of terrain it encounters -- these are just a few of the innovative advances in the industry.

Modern designs allow a wheelchair or scooter to be tweaked for the ultimate comfort and individual requirements of the user. And there are fewer things to go wrong. Bad batteries, bent wheel rims and failed bearings -- the three Bs of wheelchair repair -- have virtually become problems of the past.

Actually, the most important factor in using a wheelchair has switched from upkeep to taking the time and effort to pick the right chair for your needs and getting it adjusted perfectly, says Mike Gross, owner of A&T Wheelchair of Laguna Hills, Calif.

"I tell every customer I deal with the same thing," he said. "When you go to pick out a wheelchair, if the process is not a real pain in the rear, you're not doing it right. If you go in, pick out your chair and are out of the store in 45 minutes, you've made a big mistake.

"It takes us a solid three hours to adjust a chair to a person's particular needs. We need to find out if the back is too high or too low, if it reclines just right, how it handles and a lot of other things.

"As for maintenance, what's important is to stay on top of things and get them taken care of right away. For instance, if your front wheels flutter, it might be only mildly irritating to you. If you let it go, though, you could lose a front wheel."

The new technology is eliminating some of the traditional problems with wheelchair maintenance, Gross noted. "Now they are going to lightweight composite wheel units instead of the traditional spokes. Before, you could twist or break a spoke, and if you didn't get it taken care of right away, you could end up with a bent rim -- and that would cost you a whole lot of money."

Also, he noted, new sealed bearing units result in a much longer lifespan for the unit. Wheelchairs with such up-to-date features cost more, but they require much less maintenance.

"I'd say you should bring your chair in every six months to let someone at least look it over and make sure everything is still the way you want it to be," he said.

The reduced need for maintenance is paying off for younger wheelchair users, who are much more active than most wheelchair users their age have been in the past. There's a trend among today's young wheelchair users to get lightweight units that fit the user more like a glove than a wheelchair, Gross added.

"A lot of the younger people with a spinal injury, or with a disease that has left them in a wheelchair, have been into athletics and don't want to give that up," he said. "The lightweight chairs become almost a part of them and the user can be highly mobile. The chair becomes an extension of them and they are able to do a lot more and have a lot more speed and power in getting around. Today's chairs are very durable and can stand up to the demands being put on them."

An interesting side effect to using lightweight chairs also has arisen.

"It was discovered by chance that in these chairs the users' legs often are higher than their rears, and this gives their torso much more support and adds to their stability," Gross said.

For nearly a quarter of a century, Fred Martinez has honed his expertise in wheelchair fitting and maintenance, first in New York and now at Ability Center in San Diego. He points to new sealed batteries as the single best advance for users of power wheelchairs as well as motorized scooters.

"In my experience, a good 90 percent of the problems with power units has been the battery system," he said. "With the traditional acid batteries, the user or caregiver has to keep a close eye on the water level in the batteries. If the water was low, the battery wouldn't work, and if it were overfilled, battery acid would leak out and destroy the battery and the wiring. The sealed batteries often are gel-based, and you never have to worry about leakage."

Other modern advances have eliminated maintenance cares, too, he noted.

"Today's electronics are solid state and so compact that we very rarely encounter problems like we did in the early units," Martinez said.

"And the motors have become so simple and durable that you shouldn't have any trouble for years and years as long as they are checked at least once a year and you have them cleaned out and the brushes replaced. And with the new airless innertubes, they have virtually eliminated flat tires on wheelchairs."

It's important to have a good relationship with a wheelchair dealer or repair facility that you can trust, Martinez stressed.

"Maintenance is a team effort," he said. "If you bring your chair in every six months to have the battery connections tightened up along with any nuts or screws that you've noticed getting a little loose, it can save you lots of money down the road."

Your maintenance expert also will be able to spot impending problems and head them off, he said. Plus, needed adjustments to seats, leg rests, side panels and other key parts of the chair can be made before they affect the user negatively.

"I used to take wheelchairs completely apart and oil, grease, tighten and fix hundreds of parts," Martinez said. "It would take three hours or so. Now it takes only a few minutes to make sure everything is OK. We never charge unless there is something really wrong."

There still are minor wheelchair maintenance tasks that can be handled easily at home with a screwdriver, wrench, pliers and a little common sense, but anything at all complicated should be handled by a professional, Martinez points out.

"It's best to get it done by someone who knows the ins and outs of your wheelchair. What seems simple may actually be an indication of something more serious," he said.