Restaurants tend to go through similar life-cycles. They open up to much talk and publicity, people arrive in numbers to check it out, its name is briefly on many lips. After the initial brouhaha has died away, a restaurant starts to build its real - not ephemeral - customer base. By the end of year two, if that customer base is big enough, the restaurant will probably survive for at least seven years.

What happens after that is interesting. If a restaurant can continue to build on its reputation and keep its standards up, re-invest its profits in maintaining and improving its dining room, then it can move on to the next stage when it becomes widely known. Being well known is good for a restaurant; taxi drivers will pass the name on to visitors, the concierges in hotels will recommend it, dining guides will list it. When a restaurant reaches this point, it's good for another seven years.

Because fashion is by nature fickle and food fashions change as surely as haute couture does, a further seven years becomes very hard to achieve. Very few restaurants reach the classic age of majority, twenty-one. In part that's also due to the fact that running a restaurant is very hard work. Chef-patrons get tired, manager owners get tired too, they retire, they sell up, they move to Portugal to play golf and drink wine in the sun. Sometimes the restaurant will metamorphose into another kind of restaurant in order to keep up with changing fashions, but for a restaurant to remain the same and stay open profitably for years is unusual.

I can think of very few restaurants that have achieved this rare feat, but this week I was in one that's not far off doing just that. I went to 'The Orchid' to meet my friend Michael Colgan, who I haven't seen for while, so that we could catch up over dinner. Michael knows The Orchid well, he's been going there for years - nineteen years to be exact. You see it's been in business that long, so the magic twenty-one years isn't too far away. It's possible that The Orchid is an example of a theory I've expounded before: if your restaurant never becomes very fashionable, it can never fall out of fashion.

Unless you know where it is, it's easy to miss. It's at the Ballsbridge end of Pembroke Road, in the basement of one the large terraced houses that line that road. Walk in through the understated entrance and you're in a very nicely furnished room that's much larger and longer than you'd have guessed from outside. The tables are well-spaced, they're topped with good linen and the tableware is good quality.

What I did know about The Orchid was that it has a reputation for the high standard of its service. It lived up to its reputation on the night: from the moment we arrived the service was both friendly and attentive. The menu, like many Chinese restaurants, is long and has a bewildering array of choices, running the gamut of Dim Sung dishes, through pork, beef, lamb and prawn dishes. Eventually we decided upon the stuffed crab claws followed by prawns in a black bean sauce for Michael and the spicy squid followed by sweet and sour pork for me. From the wine list we picked out a Macon Lugny priced at €29, which went very nicely with our choices.

While we snacked on our prawn crackers waiting for the starters, we talked of Samuel Beckett. It's the centenary of his birth next year and Michael is organising a theatre festival to mark the event. With the help of John O'Donoghue our minister for sport and tourism, it looks like the centennial will be snatched from the French and placed firmly in Ireland where it really belongs. Nice to be celebrating another Irish writer so soon after the Joyce festival.

The starters arrived and two huge crab claws arrived on Michael's plate, puffed up with a prawn stuffing. My plate had a generous portion of squid rings which had been well cooked in a crisp batter. Michael kindly gave me a taste of his crab claws, which tasted as good as they looked.

Our main courses were equally good and came on hot platters which were placed on warmers in the middle of the table. A bowl of plain, boiled rice and a bowl of egg-fried rice accompanied these dishes. The black bean sauce on Michael's prawns gave an interesting contrast to the prawns, which were large and firm and made for a good dish. My portion of sweet and sour pork looked as though it was for two people, but little by little I managed to eat it all and I enjoyed it.

Purists may tell you that the meal I've just described is about as Chinese as Irish Stew, claiming that that these are dishes that you'll never find in mainland China. That may well be true, but whatever the provenance, the food that we ate was precisely flavoured, well cooked and professionally served. It wasn't knock-your-socks-off memorable, but it's true to its menu description and it's simplicity of preparation was in my view very much a plus point.

I suspect that The Orchid is the sort of restaurant that never serves a bad meal, it seems to have got consistency into its operation, something that might well account for its longevity. The bill for the evening came to €111.60, which didn't include a service charge.