[foobarrio]

Do you really have to actually service them at 5 year intervals? I have Seiko SKX with a 7S26 movement that still people routinely say it goes 10+ years without a service. When you do, it's about $100 since the movement is so common and cheap. Seiko and Casio both make fine quartz watches that are solar powered and have much lower maint cost than an automatic watch (though typically not seen as a nice or luxurious watch). The swatch thin-line watches are quite nice and replacing the batteries is cheap.

[achompas]

Well, you don’t have to, but the watch is basically a total loss once it requires a service. You could service it preserve the sentimental value, but if OP wanted a hearty watch they would’ve bought a G-Shock or quartz.

(Tangent: folks in the watch community are “particular” about the watches they purchase. In 2018 quartz is out of style, even though they run longer and resist shock more than automatic watches. In my mind, OP traded one trendy watch - the Apple Watch - for another watch trend.)

[btian]

Probably not. But if you own a Rolex Daytona, you would, just for peace of mind.

[foobarrio]

Rolex used to replace all worn parts in their movements as part of their servicing at no extra charge. Do they still do this? If so, then I would push off the service as long as possible. If you wear out a bunch of parts after 20 years they'll be replaced in a single service. I think the average service interval for them is 10 years (not that they recommend that but what people usually do) and the servicing is like $750 last I remember.