Not sure I would take too much advice from the place you bought this from...from the horse's mouth...

 

I got my new Speedmaster at an Omega Boutique. It just goes to show that no matter where you go, there is a lot of puffing going on.

When I was in the store, the actual guy that was selling the watch told me 8 years which jives with the maximum interval you quoted from the website however, another sales guy within earshot said, "no, the 3861 has a 10 year interval" referring specifically to the new movement. I suppose it's possible there is some newer information that they have in regards to this specific movement and the website is generic for all the watches. I'm inclined to believe that all the modern movements would need service at the same time given similar environmental conditions.

My old Seamaster 300M went for just over 23 years without any service at all and was still keeping decent time and working just fine. I was just a watch user and did not know any better before. Now, I'm a watch enthusiast and won't take that chance anymore.

Honestly, with this new watch, I'm more than a little bit paranoid so I'll probably send it off for service a couple months before the 5 year warranty expires.

I wonder if the local technician at the boutique can do the water seal check and service if nothing else is needed. I'll find out in a year I guess . . .

Thanks,
Frank

 

There's nothing about the 3861 that would make it any different from a service interval standpoint than any other Omega...

 

When auto makers started including “free service for the first 50k miles”, the cars miraculously no longer needed service. Words like “lifetime fill” and “self calibrating” started showing up in adverts. The cars hadn’t changed, the fluids hadn’t changed, the mechanical technology hadn’t really changed- but the marketing did.
Always listen to the engineers, not the marketing weenies.