Cartier mechanical watches are famous for their precision. Generally speaking, Cartier mechanical watches will be guaranteed to maintain an accuracy of -4/+6 seconds per day. Such accuracy is ensured by the strict inspection of the watch before they reach consumers and the rigorous quality control process of Cartier's complex manufacturing process.

However, this accuracy can only be achieved under very specific conditions. For example, the watch must be placed in a temperature range of 10°C to 40°C and should not be exposed to strong magnetic fields or heavy vibration. In addition, the accuracy of the movement can degrade over time due to aging and may require service every few years.

In general, the accuracy of a Cartier mechanical watch is dependent on several factors. Firstly, the watch must be kept in the ideal temperature range and away from heavy vibrations and magnetic fields. Additionally, the accuracy of a Cartier watch typically degrades slowly over time and requires periodic cleaning and maintenance. Finally, the level of accuracy of a Cartier watch depends on its overall quality - higher quality watches tend to be more accurate than lower quality models.