It might not be as convenient or complex as a perpetual calendar, which will automatically track the days (including shorter months and leap years) until 2100. But the annual calendar is a heck of a lot cheaper, and therefore relatively popular. As its name suggests, the annual calendar has to be set once a year.
The calendar mechanism has been programmed for months with 30 or 31 days, a relatively simple task since the choice is binary. But it has to be advanced manually on March 1, since February has only 28 or 29 days. One of the latest is the Omega Globemaster Annual Calendar, which is unusual for having the months of the year on the edge of the dial, instead of the usual window-style display.