Mechanical watches have a number of moving parts that are lubricated to reduce friction. Over time, these lubricants degrade and will need replacing. Replacing lubricants, together with cleaning and regulating your watch, is all part of a service that should only be undertaken by a qualified watchmaker. Seals that keep your watch watertight will also degrade over time. We recommend getting your watch serviced every three to five years for most Oris watches. With Calibre 400 Series watches the recommended service interval is 10 years.