Ulysse Nardin watches are all top brands. It is recommended that you take them to a large professional and formal watch repair shop for repair. In Hefei, you can go to the 13th floor of the Yintai Center Office Building, Changjiang Middle Road, Luyang District, where there are professional technicians and maintenance equipment. Reasons why mechanical watches run inaccurately or slowly: 1. Magnetism of the watch: Excessive contact of the watch with objects with magnetic fields causes the watch to be magnetized, causing the watch to be inaccurate. After being magnetized, the watch may stop, slower or faster. After the watch is magnetized, the magnetism will not disappear on its own and requires demagnetization and repair to return to normal. So you have to go to a professional watch repair center to demagnetize it so that it can return to normal. 2. Insufficient maintenance: Mechanical watches should be maintained once every 2-3 years, and quartz watches should be maintained once every 4-5 years. When maintaining a watch, the movement should be completely disassembled, cleaned, oiled, reassembled, adjusted and its functionality checked. or repair or replace any worn or faulty movement components. If the watch is lack of maintenance, parts will wear out and the sludge will dry up, which will affect the normal running time of the watch and make the watch appear to be fast and slow. Regular maintenance of the entire machine can effectively prevent various malfunctions of the watch. 3. Mechanical failure: Mechanical failure such as hairspring failure, escapement system failure, sliding teeth of parts, etc. may cause the watch to appear fast and slow. Therefore, when the watch displays abnormal timing, you can first pull out the crown and take it to a professional maintenance organization for a maintenance technician to check the cause. 4. Of course, mechanical watches may be faster or slower, and may also be caused by violent impact, water intrusion, etc. The cause is complicated and requires maintenance technicians to perform repairs according to the specific circumstances.