A complication that adjusts for 30- and 31-day months, requiring correction only once a year in February.
Extended Explanation:
Introduced by brands like Patek Philippe, the annual calendar sits between the simpler date function and the highly complex perpetual calendar. It provides practicality for everyday use, requiring manual adjustment just once annually. This makes it a favorite among enthusiasts who want sophistication without the high cost of a perpetual calendar.
