Perpetual calendar tune up very complicated, according to the author's experience, it is best not to try their own best, to the professional agencies or brand more reliable aftermarket. Because of the one hand, the calendar as one of the top three complex functions (the other two are the tourbillon and three asked one), so many watch brands so far can not produce perpetual calendar watches, showing the complex "complex." On the other hand, even if you are more professional, it is not easy to adjust the calendar. There are still some special issues requiring attention. For example, you can not adjust from 10 pm every day to 2 am the next day because This period of time is exactly the period of time when the calendar's gear has been fully engaged. At the same time, it is impossible to adjust the month between the 26th and the 2nd of the following month. If this time is adjusted, the movement will often get stuck. Moreover, almost all calendar watches are forbidden callback. Visible, adjusting the calendar is not really an easy task, and in view of perpetual calendar watches are often more expensive, in order to avoid a slight accidental loss, it is best to give professional organizations or brand after-sales processing.