ABOUT THIS TIME of year, for all but one of the last 21 years, Mike Murphy has closed up his Wayne house and headed 100 miles southeast, his perch on the North Wildwood beach clean and ready for him once again. An actor, model and corporate spokesman in cooler weather, when the first warm ocean breeze hits, Murphy is back up on the lifeguard stand five days a week.

"My office is the beach. I've been doing this since college and can't get enough of it," said Murphy. "I compete in the [lifeguard] competitions and love teaching fourth-graders in the junior classes."

Murphy has never wanted to buy a place, always renting a couple of blocks off the beach.

"I guess, yes, you could say I'm addicted to the Shore. I wouldn't want to be anyplace else for those nine weeks," he said.

According to Realtors, Murphy and his fellow perennial Shore renters will find a stable market this year. Despite the seeming threat of a slower economy and higher gas prices, little has changed in the last couple of years - neither prices nor availability, except in a few specialized cases.

"There are a few more properties here," said Mark Grimes of Ocean City Realty, "and they overbuilt a little bit with condos in North Wildwood, but there have also been more people renting early, so for those coming now, it will be about the same as last year - the best weeks and best properties gone, but still some places to rent here and there at a decent price."

That "decent price," according to Grimes, is in the $1,000-to $1,500-a-week range for a three-bedroom apartment three blocks from the beach, going up to $3,000 for similar digs a block from the beach.

In Sea Isle City, said Ian Lazarus of the Landis Co., you'll spend slightly less - perhaps $2,500 to $2,800 for a side-by-side townhouse a block from the beach.

Realtors in North Wildwood said a week at a new, three-bedroom condo about a block from the beach or boardwalk would be $1,500 to $2,000, which is slightly less than the peak reached about three years ago.

Whatever the price would be in Ocean City, though, Lou Greenwald would be there. The New Jersey Democratic assemblyman from Voorhees, who is now 41, has been going there as a renter every summer since he was a boy visiting his grandparents at their rented place.

"My other friends from Cherry Hill would go to Margate and Stone Harbor," said Greenwald, "but for us it would be Ocean City, because all four of my grandparents loved it. It was playing Wiffle Ball with my grandfather and going to Mack & Manco's on the boardwalk for pizza and Kohr's for custard."

He said his mother, Maria Barnaby Greenwald, would come to the Shore and transform from tough politician (she was the mayor of Cherry Hill) to just plain Mom, making baked beans and potato salad for picnic lunches.

"It has always been for a couple of weeks in July, and now I do it with my kids," Greenwald said. "It never gets old."

For Karen Ferguson, who grew up in Collingswood and now lives in Haddonfield, summer rentals at the Shore started with her parents and their siblings in Wildwood.

"It was fun, but my parents got tired of the drive" and started going to Ocean City, which was closer, she recalled. "Now my twins are 19, and we were thinking of not renting for the first time. When we told them - they are freshmen in college - they screamed, 'What are you thinking? Of course we are going to rent at the Shore.'"

Talk of the slower economy and higher gas prices thwarting the Shore rental market is misplaced, said Grimes of Ocean City Realty. A few bucks more in gas hardly stops the regulars.

"It is what they do, what they save for," he said. "People who love the Shore aren't going to let $4-a-gallon gas stop them from the smell of the beach."

Jim Dougherty certainly isn't. He and his wife, Carol, have dragged their five daughters to the Shore all their lives. (The girls are now 14 to 28 years old.)

The Doughertys rented for two to four weeks in Sea Isle City during the 1980s. For the last 15 years, it's been the same place at 27th Street and Asbury Avenue in Ocean City. He estimates he has spent an average of $6,000 a year in rent in recent years, slightly less in the past.

"I suppose if I had that, say, $175,000, I could have bought something, but then I would have had to take care of it," he said. "Renting, all I have to do is clean up a bit at the end. I know more of the neighbors than the owner does, because I am down here every year.

"And I am at the Shore, without any worries," he said. "That is what I want my summers to be." *