Luxury watch-owning friends of mine are always put out by how much it costs to service a mechanical watch. The tone is always the same. “I spent £5,000 on this watch three years ago, took it back in for a check-up, and they want £500 for a service. Five-hundred quid! That can’t be right. Can it?”

Well, yes. It can. And depending on the watch, it can be a lot more than that too. Servicing a mechanical watch, even a simple one, is the hidden cost of ownership.

Because it’s so much more expensive than people expect, watch servicing provokes moral outrage, like a stealth tax. It creates that same feeling of powerlessness, too. “If I don’t get it serviced,” those same friends fluster, “they say my watch might stop – and that would cost even more to sort out. How am I going to explain that to my wife when I’ve promised her a week in Tuscany next summer?!” etc.

I can understand this. The first time you come face to face with the realities of watch servicing it does feel like someone’s pulled the wool over your eyes.

With a car – so often a watch comparable – you know you have to pay to get your brake light fixed, because if you don’t, you might get arrested. You also know that if you don’t replace your tyres, you’re playing Russian roulette with your life.

But it’s different with a watch. Unless you’re negotiating with Columbian drug smugglers, a watch is almost certainly not going to save your life. There’s no gun to your head obliging you to pay for a service. And you wouldn’t be the first to eschew coughing up another cash-wad if you chanced it – there’s always your phone, after all.

This, though, is where owning a mechanical watch is very different to owning a car, and much more like owning a dog. (A dog with pedigree, obviously.) It’s a responsibility. It asks something of you. Not as much as a smartwatch – that would make it an irritant. And you get back what you give.

Patek Philippe’s now 20-year-old strapline (that ‘you never actually own a watch…’) may over-romanticise watch ownership, but the point about you ‘looking after it for the next generation’ isn’t only fluffy marketing. Tend to it properly, and a proper watch will be something your children’s children remember you by. My grandfather died 20 years ago, but I still have his Rolex.

To put the cost of servicing in perspective, it helps to understand how a mechanical watch works. Inside a watch – whether it’s a £400 Hamilton or a £100,000 Roger Smith – is an escapement, a device that regulates the way a mechanical movement uses power.

The escapement holds a balance wheel that, in most watches, vibrates eight times a second, or 28,800 times an hour. That’s what makes the ticking sound. Assuming you wear your watch every day and keep it wound, that’s more than 250 million ticks a year. Still paying attention at the back?

Eventually, those moving parts start to wear out, which is why your watch needs a service. In a service, a watchmaker takes a watch to bits, cleans its tiny parts, replaces them where necessary, relubricates them and then puts the whole thing back together again.

This requires skill. Add in a case polish to get out those dings and scratches, and the same for a bracelet if your watch has one, and you begin to understand why a watch service might cost more than a couple of pints of lager and a bag of pork scratchings.

What’s also important to understand is that watches need servicing quite regularly. The conventional wisdom on service intervals for a new watch is three to five years, but privately senior brand folk will admit that the time to pass your watch to the men in white coats is when it starts under-performing, whenever that may be. Just don’t leave it too long.

But no matter how justifiable, there’s no escaping the fact that servicing is a corrosively expensive business. The good news is that brands are beginning to cotton on to consumer frustration and ploughing their reserves into developing watches that can go longer between services. Advances by the likes of Rolex, Omega and even Tissot are at least taking some of the sting out of long-term ownership.

Rolex’s recent innovations include Calibre 3255, launched last year. It’s more efficient, shock-resistant and anti-magnetic than the company’s previous movements, but at the moment it’s only available in Rolex’s Day-Date 40, a watch that only comes in precious metals (with price tags to match).

One of the most significant things about that movement was that Rolex slapped a five-year warranty on it, and said that it could go up to 10 years between services – an unprecedented claim from a mechanical watchmaker.

Then, in June, it quietly ushered in a new era for the company, attaching the same warranty and recommended service intervals onto every new Rolex watch. I don’t want to overplay this development, but this is big news for the man on the street watch buyer.

Rolex isn’t alone in pushing watchmaking technology. Omega’s new line of Master Chronometer movements features a number of low-maintenance moving parts, some in silicon – watchmaking wonder-stuff that’s low-friction and therefore requires no lubrication. Those come with a four-year warranty and need servicing every four to seven years.

Tissot, which makes four million watches a year, has also just introduced the Ballade, an everyday timepiece that becomes the first mechanical watch with silicon parts to retail for under £1,000. All positive signs.

So, yes, there’s no getting away from it – servicing a mechanical watch costs a few bob. But it’s money well spent. Unless, that is, you want the legacy your grandchildren remember you by to be a lock of hair and a front tooth.