The Rolex Oyster Perpetual is a classic watch that never goes out of style. This is a time piece that has been to the summit of Mount Everest, sunk into the Pacific Ocean and baked to 500 degrees F, and it still looked and performed great. Retail price for a Rolex is $5,000 to $10,000, so remember the adage, "You get what you pay for" when your friend tells you he can get you one for just $1,000. Telltale signs on the watch will warn if you bought a fake.
Consider the source of the watch. Luxury department stores and jewelers are the best places to buy a genuine Rolex. People do buy them first- and second-hand on eBay, provided that the seller can authenticate the piece. If you think you've found a genuine Rolex for $300 in New York's Chinatown, the vendor probably also has a bridge he can sell you that leads into Brooklyn.
Test the Rolex's heft in your hand. This is a solid watch and should carry some weight to it. Does it feel flimsy or lightweight? The watch's bands should also be solid, not hollow.
Look at the second hand. If it moves in small steps or jerks, immediately suspect the watch. The Rolex is know for a second hand that makes a continuous, smooth sweep that is hard to replicate.
Check the reference numbers on the case. Between the lugs on the side of the case are the watch's serial and case numbers. They should be nicely engraved and very smooth. These digits will be shoddily engraved on a fake Rolex.
Flip the watch over. Examine the holograph of the Rolex crown logo on the back of the case. The holograph should shift when you move the watch around.
Smear some water over the watch's face. Rolexes are made of sapphire crystal, and its extremely smooth face will make the water pool together. This won't happen on a fake with a regular glass face.
Drop the Rolex in water. The Oyster Perpetual has been to the bottom of the ocean, after all. Your watch should work fine after being submerged for several minutes.
Always ask for a certificate of authenticity when making an expensive purchase.