It’s a brand that collectors swear by. But, what is it with Patek Philippe that makes it tick. Henry Vo answers.

Patek Philippe collectors aren?t like other watch collectors. They aren?t flashy; they don?t have to be. That?s because Patek Philippe?s understated elegance bespeaks confidence. Simply put, Patek owners know they have the very best in craftsmanship, heritage, and design sitting on their wrists ? and once you?ve owned a Patek Philippe, nothing else will do. Here are some reasons Patek owners love their watches so much, and some selections from our online-only sale at Christie?s Watch Shop.

1. The Scarcity

Patek Philippe, Wempe, 125th Anniversary, Ref. 5125. Platinum, 2003. $98,000. This watch and those below are offered in our online-only sale at Christie?s Watch Shop It?s said that fewer than a million Patek Philippe watches have been made since 1839. That?s fewer than some very high-end Swiss manufacturers make in a year. Patek production is so detailed it takes nine months to make the most basic Patek Philippe watches in production and over two years to make some of the more complicated ones. That?s one big reason why the numbers are so low. Meanwhile, demand is growing around the world. Some Patek Phlippe watches are in such demand that buyers must submit to an application process to prove they are high caliber enough as collectors. (Or you can just call the Christie?s Watch Department and get one in a private sale tomorrow!)

2. The Design

Pat...