Patek Philippe 5035 (Pre-owned - Excellent) — USD 24,499 on eBay

The Patek Philippe reference 5035 introduced the annual calendar complication to the brand's regular production lineup, marking a significant development in accessible high horology. This reference automatically accounts for months with 30 or 31 days, requiring manual adjustment only once a year at the end of February. Its introduction provided collectors with a sophisticated calendar function that was more practical for daily wear than a perpetual calendar, yet still showcased Patek Philippe's technical prowess. The 5035 features a 37 mm case, offered in 18k yellow gold, white gold, or rose gold, with a smooth bezel. It is powered by the automatic caliber 315 S IRM QA, which includes a power reserve indicator, date, and small seconds. The movement provides a power reserve of approximately 45 hours. A sapphire crystal protects the dial, and the watch is water resistant to 25 meters. This reference appeals to collectors seeking a historically important Patek Philippe annual calendar. Its design is characterized by a balanced dial layout, typically in silver, with sub-dials for the month, day, and date, along with a power reserve indicator. The 5035 was produced from 1996 to 2006, establishing the annual calendar as a core complication within the Patek Philippe collection.