I also have a 30 year old Omega watch. Every five years that goes back to Omega, it’s away for about a month and costs £2-300 each time.
My experience is that while lifetime and cost are often correlated, they aren't always, the ratio is often a curve, and the curve is different for every product. My $10 Casio watch has outlasted some nicer watches costing more than $100. But I once made the mistake of buying a $40 pair of shoes, and they were unwearable within a few months.
Another example is that high-end suits with high thread count are supposedly less durable than less expensive suits, because the finer, more comfortable fabric is also thinner and wears more quickly.
My oldest pair of shoes are going on 11 years, and look even better than the rest after one re-sole.
That being said, my everyday Omega (a PlanetOcean diver) has gone for 11 years without a service and still keeps excellent time; once timekeeping deteriorates, I’ll have it cleaned, lubed and adjusted at my local watchmaker’s.
Oh, and the case will be refinished over my dead body; it has more or less literally gone to war with me, got banged up a bit, lived to tell the tale and is still ticking.