Since watches are oiled with the modern synthetic stuff, how much time should pass before it needs another service? These new oils shouldn't break down or migrate like the older sperm oils. Is it conceivable that if a watch is kept in a clean environment it could run without damage for years, instead of the recommended yearly cleaning from back in the 1940's and earlier? It is my opinion that frequent servicing is not necessary if modern oil is used and the watch runs OK. However, I realize regular service is recommended by manufacurers. I would be very interested in hearing opinions on this.

Scott, i would think it would depend on a few things, like is it worn daily? How well the case keeps out dirt? The environment it is worn in?Perhaps even the climate could be a factor, high humidity ot cold.
I am not a expert, these are just my thoughts, i would say if worn every day at least a clean and oil 3 to 4 years.

The philosophy of the old watchmakers that I have known was that--"if the watch is running well and keeping good time, leave it alone". Therefore, when I acquire a watch, if there are no problems, I don't rush right out to clean it. Some of the individuals who told me this over the years had been in the business over 50 years. I would think they would know what they were talking about.

Just my two cents.

Tom