I have just had my 19 year old Brietling Aerospace serviced by the manufacturer. I was expecting a silly bill, but for £298 the following work was done: Clean & polish all over, new glass, new hands, new battery and believe it or not, totally new guts. My watch now has loads of new functions that I don't know how to operate. I reckon that's good (well reasonable) value for money, even if you have to pay courier rates to get it to the factory.
PM