Six years ago, a generation of television viewers went into mourning. In May of that year, Channel 4 aired the final episode of Friends, the hugely successful US sitcom that turned six hitherto unknown actors into household names and showed us that Americans can do irony after all. It was, we were told, the end of a glorious era. But now it was time to let go and bid our farewells. Life would never be the same again.

In the event, not much changed. While the actors and audiences moved on to new pastures, Friends never went away. It has stayed on our screens on an endless cycle of repeats, with each episode somehow maintaining viewing figures in the hundreds of thousands and insistently reminding us of the series' status as the most popular sitcom of all time.

In the intervening years, it has become a kind of televisual grout, filling the gaps between the more up-to-date and pressing business of daily news, feature films and Wife Swap USA. Its presence on the schedules, particularly at the weekends, has become as regular, familiar and quietly crucial a part of our routine as breakfast, lunch and dinner.

But now we are asked to don our dark suits and widow's weeds once more, since Channel 4 has announced that it is soon to stop showing Friends altogether. The news has been greeted with immense relief by some viewers, for whom the show's determinedly perky title song brings on an inexorable desire to plunge a fork into their eyeballs.

But what of the rest of us for whom the six New Yorkers – Ross, Rachel, Monica, Chandler, Phoebe and Joey – have been constant companions for nigh on 16 years? What will we do with our weekends? And, given that Channel 4 has already axed Big Brother, what on earth will they do to plug the gap?

So why exactly does Friends stand up to such relentless repetition? After all, it's not often that I will watch the same film more than once and, while I'm a fairly devoted EastEnders viewer on week-nights, even I find the continued presence of the omnibus a stupendously lazy piece of scheduling, especially in the era of Sky+.

Where Friends is concerned, it's partly a matter of quality: the writing is so good that it bears repeating. With its rapier wit, three-dimensional characters and complex relationships, Friends remains the historical marker as to when comedy drama really raised its game. Particular set pieces – Monica dancing with her head inside a turkey, Chandler being locked in a box to contemplate his crimes with Joey's ex, almost any Monica-Rachel catfight – still prompt audible chuckles, if not belly laughs. And while the show's humour is smart, it's not necessarily intellectually challenging, which surely makes it the ultimate in weekend viewing, to be watched in the grips of a hangover, while entertaining the children or preparing the lunch. When you've seen each episode upwards of five times, the familiarity of material becomes comforting, like a cherished piece of furniture or an old song that you've been absently humming for years.

Indeed, Friends' enduring appeal lies in its ability to provoke feelings of nostalgia. I was in my penultimate year of university when it started, since when the series has accompanied me through my first forays into the professional world, into a long-term relationship and the ensuing life of marriage, work and procreation. As the six characters bumbled along with their coffee-drinking, gossiping and attempts to navigate their way through everyday situations such as dating, family politics and what to do when your flatmate earns more than you do, so did my friends and I.

Friends offered a narrative for our own lives, albeit an airbrushed version with bigger apartments, more toned bodies and conspicuously disposable wardrobes. It reflected the preoccupations of a whole generation, largely – and, yes, selfishly – immune from political events, free of their families, and who looked to their circle of friends for like-mindedness, loyalty and love.

Of course, times have changed since Friends began, and not just because of the onset of a few grey hairs. Religion, politics and economics are all issues that directly affect us, whether fresh out of college, settling down or contemplating retirement. Television has got darker, grittier and, let's face it, is all the better for it. The good times, as we once knew them, are over.

All of which makes a stolen episode of Friends more appealing than ever. Its function isn't just to offer a rose-tinted view of old times, but to provide a rare half-hour of well-written, beautifully executed comedy drama. Now's the time to make the most of the time we have left. So what if we've seen it before?

They do run, run, run: shows that have stood the test of time

Father Ted

It's still difficult to watch an episode about the Craggy Island fathers now without feeling such sorrow at the loss of Dermot Morgan. The show, written by Graham Linehan and Arthur Mathews, ran from 1995 to 1998 on Channel 4, was surreal and slapstick and deeply funny. The episode 'Kicking Bishop Brennan Up the Arse' will never get tired

Seinfeld

After running for nine seasons, Seinfeld wound up in 1998 but it's still name-checked as the best sitcom ever for many people, rated a critical and commercial success. The devil is all in the detail in this largely plotless show, as Jerry, George, Elaine and Kramer try to duck life's slings and arrows. They were a neurotic and often unlikeable group but this made us love them more. Jerry Seinfeld himself never returned to form after the show ended. The Marriage Ref, his new comedy game show, has been panned

Frasier

A spin-off of Cheers, Kelsey Grammer starred in the show as psychiatrist Dr Frasier Crane for nine years. The good doctor, who also hosts a talk radio show, moves to Seattle after splitting up from his wife and takes in his police officer father who isn't able to live alone because of an injury. Its wonderful cast (David Hyde Pierce who plays Frasier's brother Niles is amazing) was a contributing factor to its success but the sibling rivalry between that duo, their respective doomed romantic escapes and their lofty intellectual aspirations provided rich comedic fodder