Mechanical watches call for regular maintenance if they are to keep running accurately. Recommended periods vary by manufacturer, typically around every five to seven years. Overhaul includes stripping, cleaning and re-oiling. Running a watch too long between services can cause accelerated wear.

The secondary watch market delivers access to pieces that are discontinued or allocated. Authentication remains the central concern. Serial and reference numbers should match the documentation. A service record influences what the watch is worth.

Full documentation carry a definite premium in the secondary market. The warranty card establishes when and where it was sold and assists the chain of ownership. An unpapered example need not mean a cause for concern, but this commands a discount.

Secondary market value varies enormously from model to model. Steel sports models from the strongest brands often sell above retail, while precious metal dress watches commonly lose value. Originality and audemars piguet royal oak documentation drive value between two identical models.