On the eve of its season four debut, MTV's hit reality show The Hills, documenting the lives and loves of four twentysomething frenemies, may be showing its age.

It was just over two years ago that the show first aired, revitalizing the MTV brand and capturing the attention of viewers everywhere. Almost immediately, The Hills—a spinoff of Laguna Beach, another popular reality series featuring some of the same sun-kissed teens frolicking in the Southern California surf—rivaled ratings for the new season of The Real World, MTV's original reality show.

By its third season, which ended last May, the show had an average of 850,000 viewers, almost triple that of another MTV staple, Total Request Live. At the same time, its characters, such as Lauren Conrad, Spencer Pratt, and galpal Heidi Montag, morphed into bona fide stars, appearing everywhere from David Letterman to seemingly every other page of US Weekly.

Despite all that buzz, some industry analysts are speculating about the show's imminent demise. The Hills could be over the hill.

Tonight's season premiere will "do well, but it's probably on the way out—that's sort of the inside word," says Peter Gardiner, chief media officer at Deutsch, an ad agency in New York and part of the Interpublic Group, a marketing communications and services company.

Gardiner's 21-year-old daughter is a fan of the show, and the buzz in her crowd is that the show is getting old. Part of that, perhaps, is that the young women at the center of the show are now all stars in their own right. They aren't struggling to make it—they already have.

But the other part is that, inevitably, successful reality shows become victims of their own dominance.

"There's a natural arc for the non-mass reality shows," says Gardiner, pointing out that even American Idol, the formerly invincible singing competition that made Fox the most-watched network, has slipped in the ratings.

Gardiner won't rule out a fifth or even sixth season for The Hills, depending on how tonight's premiere and the subsequent episodes are received. But on top of the inevitable reality show wear-and-tear, the competition for viewers is especially tough this month because The Hills is up against that other crazy-making reality series, popular among young viewers…the Olympics.

Considering that factor, The Hills' season four timing is curious. Will viewers really switch off tonight's track and field events in Beijing to watch Lauren and Heidi's epic battles out in California? MTV, for one, is hoping they will.