By Iain Blair

LOS ANGELES— When to slow down and retire? For most people in their 60s the decision is a no-brainer – the sooner the better. But in the rare air of movie stardom, where careers are fueled by a mix of talent, ego, vanity and, sometimes, cosmetic surgery, it seems to be a far harder decision.

Hollywood’s latest example is Harrison Ford, 65, the aging archeologist hero of "Indiana Jones and the Kingdom of the Crystal Skull," which debuts around the globe next week after its world premiere at the Cannes film festival.

But Ford is not alone in trying to maintain an image as a strapping young action hero. Movie icons from the 1960s and 1970s from Al Pacino to Sylvester Stallone still insist on winning the day and getting the girl — even if she’s 40 years younger. Even Robert De Niro has taken questionable roles lately, playing a cross-dressing flying pirate in "Stardust."

A few, notably Jack Nicholson, Warren Beatty and Clint Eastwood, seem to have accepted the idea that their leading man status is now well behind them. Beatty is now a sort of elder statesman in Hollywood. Eastwood is an Oscar-winning director, and Nicholson is, well, Nicholson.

Ford is luckier than most. After a long string of dismal thrillers and dramas, the star is back in a role which, in three previous Indiana Jones movies that ending with "Indiana Jones and the Last Crusade 19 years ago, have generated around $1.1 billion at global box offices.

"Suddenly he’s cool again and on every magazine cover in America," notes Leonard Maltin, "Entertainment Tonight’s" film critic/historian. "But without that role maybe he’d be in the same boat as the others."

Moreover, early word on "Crystal Skull" is that Ford and creators Steven Spielberg and George Lucas have insisted "Indy" roughly match Ford in age. Some of the heavy lifting on the action front goes to Shia La Beouf, his 21 year-old co-star.

For some aging icons, the name of the Hollywood fame game now seems to be "Take The Money And Run." De Niro and Pacino, in particular, have been pilloried for career choices over the past decade that include "Gigli," "Godsend" and the aptly-named "Two for the Money."

"De Niro has to support a lot of family, the Tribeca Film Festival, and his whole little empire of hotels and restaurants," said Todd McCarthy, chief film critic for show business magazine, Daily Variety.

"I guess that was his prime motive, because in the early part of his career he seemed to be very shrewd about what parts he’d select and what directors he’d work with," McCarthy said.

McCarthy added that for people like Ford, being called "The Sexiest Man In The World" as a young star in magazines gives them an image that is hard to give up.

The result is the spectacle of a 68-year-old star like Pacino surrounded by young women in "88 Minutes," his latest film, which was panned by critics.

Clinging to public exposure is nothing new for stars, and in some cases it can pay unexpected dividends. In the early 1960s, Bette Davis and Joan Crawford teamed up for what was seen at the time as a somewhat tacky, if entertaining film, "Whatever Happened To Baby Jane?"

Maltin noted that in youth-oriented Hollywood, few films with big Hollywood budgets and wide releases are being written for 60- to 70-year-old actors. Even Nicholson, 71, "did an Adam Sandler comedy and his ‘The Bucket List,’ was the most sentimental movie he’s ever made," notes Maltin.

Still, "Bucket List" proved to be a box office hit, and Nicholson has been able to mix big Hollywood films like "List" with award-winning fare such as "About Schmidt."

Meryl Streep also has survived poor movies and managed to expand her already formidable range. She gamely appeared in the Farrelly Brothers’ farce "Stuck on You," and then effortlessly stole scenes from young star Anne Hathaway in "The Devil Wears Prada," earning wide critical acclaim.

"An actor likes to act," Maltin adds. "

He sees another factor in the equation. "Hollywood movies are getting dumber and dumber by the year," he said.

That news doesn’t bode well for stars in their 40s like George Clooney or Brad Pitt or nearing that age, like 37-year-old Matt Damon. Unless, that is, they move onto directing, producing or, like former "Terminator" Arnold Schwarzenegger, go into politics.