Not the Seiko 7S26 . You can get a LONG time without servicing (nothing but cleaning, inspection, and lube --- if you need an "overhaul", you're abusing it) it. A LONG time. Matter of fact, I don't even get a 7S26 serviced until it won't keep proper time.
NOT trying to argue with you, had many Seikos and loved 'em. However, what I call an overhaul is what you are calling service - clean, inspect, lube, goes for over $100. If you wait till it's not keeping time, it's not really a serviceable piece of gear for the field.
The key with mechanical watches is to find a LOCAL competent watch maker. Emphasis on competent. And don't go to jewelry stores as they likely farm it out to that local watchmaker and mark up your cost to twice what they pay the watchmaker. I've seen that scenario too many times.
I had one, great little shop, did good work, not cheap though.
The most frequently I have any mechanical watch serviced is every seven years. Not my Seiko 7S26s though. They go longer. And for a time-only movement I pay less than $100 for a simple service. Even at 7 years that's equates to less than $1.20 a month.
That's true, many of them are never serviced and run fine for decades.
G Shocks are good, but too many times have I seen guys in the field without a working watch because of a failed battery and an inability to get a replacement.