The yearly surge of health-club memberships has started. With more than half of the country overweight, getting into shape is one of the top New Year’s resolutions.

According to the International Health, Racquet & Sportsclub Association, more than 8 million Americans joined a health club in 2001, with almost one million doing so in January.

But before people rush out and join the first health club they find, they should stop and think about what exactly their goals are, what kind of services they want and how much they’re willing to pay, experts say.

“There really are two different kinds of health clubs these days,” says Gregory Florez, a spokesman for the nonprofit American Council on Exercise. “Ones who want to lock you into a membership and hope you won’t show up, so they can resell that membership, and ones that want to help you reach your goal.”

There’s also a balance between price and personal service: “If you’re looking for personal expertise and hands-on guidance, expect to pay for it,” he says. A large chain will generally have lower prices, he says.

“There’s so many different things that people want,” says Tracy Harrison, director of sales and marketing for the Signature Athletic Club in North Dallas.

The club, one of only 44 national locations and situated on 13 acres, is costlier than larger-scale operations but features many personal services, she says.

In contrast, Bally Total Fitness, one of the nation’s largest chains, has 380 outlets. Personal trainers come at an extra cost, but can help design a custom program.

“It’s most important to find activities that are going to be fun for you, whether it’s racquetball, whether it’s aerobics, whether it’s tae kwon do,” says Mike Divello, national director of personal training for Bally.

Clubs differ in how they charge; some charge only month-to-month, while others have multi-year contracts.

Florez recommends reading a contract closely — particularly to check for ways it can be canceled if, for instance, you develop a medical condition that forbids working out, or if you’re dissatisfied with the conditions at the club.

In addition, you should try out the club and the equipment you plan to use, to make sure it works and you’re happy with the atmosphere and level of assistance.

“Absolutely go on a trial visit before you sign anything. Don’t ever just go for a quote-unquote tour — go for a workout,” Florez says. “You’re making an investment in your health; use the same due diligence that you would in any other health decision.”

“Try whenever possible to get a trial membership that can be applied to a long-term membership. That’s very competitive right now,” he says. “They won’t always offer this option, but it never hurts to ask.”