Don’t miss this handy freebie: a perpetual birthday calendar that’s perfect for keeping track of birthdays and other special ...

In the early 1990s, Patek Philippe had long been known for its elegant time-only Calatrava models, and, at the opposite end of the horological spectrum, its perpetual calendars, perhaps the ...

Long before sustainability became a trending topic, people invented reusable, perpetual calendars, but the non-digital versions of these are sometimes complicated tables that are hard to interpret.