Vintage Levi's Jeans Guide - Watch Pocket

 This small denim pocket made its appearence in 1902, and has gotten progressively smaller since then due to the demise of use of what it was initally designed for.  It is now refered to as a coin pocket.

It is also worth noting that you should check the inside of the stitching of the pocket.  If there is a redline or selvedge edge(see below) on the inside of the pocket then that pair of jeans are quite rare and valuable to collectors.  They may fetch from the low hundreds for a pair of jeans in poor condition to well into the thousands for a mint pair of levis with it.  These prices are from watching eBay, individual collectors or vintage clothing dealers may pay more.

Era:Early 1900's
Jeans were equiped with pocket held by rivet and stitching

Jeans have a pocket size between 3.5-4 inches

Era:  During World War II
Due to materials rationing, rivets were replaced by bartacking

Pocket on jeans is now smaller and called a coin pocket.

Redline or selvede edge on inside pocket - can either denote highly collectable vintage jeans piece, reproductions, or fakes.
Fakes, however usually have it on the outside surface of the pocket.