The Breakdown: The $140,000 Watch

The Works As the number of moving parts goes up, so, too, does the price. “Complication” watches—those with functions beyond just hours, minutes, and seconds—reign in this respect. The Datograph Perpetual is packed with more than 550 separate gears, screws, weights, and springs, compared with about 130 for a noncomplication watch. But the tally can go far higher: The Patek Philippe Calibre 89, reportedly the most complex watch ever made, has more than 1,700 parts.

It’s a Date To help ensure the accuracy of the Datograph Perpetual’s calendar, testing at the Lange factory includes machine-pushing the date corrector button 50,000 times, while a camera monitors the watch at 1,000 frames per second to check that it faithfully reverts to midnight. The result is a calendar that, if the watch is wound every 36 hours, won’t need to be manually corrected until 2100 (secular years, or those that divide by 100, throw off the date-keeping by a single day).

Interior Decorating Lange watchmakers engrave each piece of the movement with a design—some are textured in a figure eight, others in a circular or striped pattern—to reinforce and strengthen it. The engraving style is unique to each of the company’s 250 watchmakers, who also handcraft their own extremely precise tools.

Forging Ahead In a bid to keep their complications running smoothly, luxury watchmakers tap corrosion-resistant metal for their cases and highly calibrated inner workings. Lange’s movement is untreated German silver, a copper-zinc alloy that’s tougher than brass. Rolex favors a robust stainless steel alloy for its famous Oyster Perpetual. Some lines go with a more precious option: All 224 parts in Jaeger-LeCoultre’s Reverso Septantième movement are 18-karat white gold.

Clean Sweep Most wristwatches with a stopwatch function, or chronograph, require three buttons: one to start timing, one to stop it, and one to reset. The Datograph Perpetual uses a complex “flyback” chronograph (originally developed for pilots), which needs just one button, since it automatically restarts itself.

Relative Merits As the product of a German family firm founded back in 1845, the Datograph Perpetual has a pedigree to match its hefty price. But it also has some jaw-dropping company. Vacheron Constantin produced the $1.6 million Tour de I’lle complication to commemorate its 250th anniversary, in 2005; Blancpain, with 13 generations under its belt, offers the Grande Complication for the comparative bargain of $785,000.

Nothing But Time Exclusivity plays as great a role as craftsmanship in a watch’s cost. With a yearlong production process that calls for each timepiece to be built, disassembled, and put back together, Lange makes no more than 6,000 annually; only 50 to 100 of those are Datograph Perpetuals.

Datograph Perpetual, Alpha Omega, 1380 Massachusetts Ave., Cambridge, 617-864-1227; other locations; alphaomegajewelers.com.