Consequence of not servicing a Vintage Rolex?

[onthemoney]

What do you think?
I am wearing my 5512 for the past 6 months, which I bought bak then.
Service history is not known by the way, but the previous owner had it for 2 years and did not service.
Keeps time good enough for me, and I am not so picky with losing or gaining seconds.

Is there any reason should service it other than keeping time?
I do not let the watch get into water, so I don't mind if the watch is not pressure tested also.
I will eventually service it at my own time of course.

I wonder if there are consequences that I can't reverse, and for that reason I should still service the watch anyway?

Thanks for help!