Best time to trade in your iPhone is ... now

Rumors are rampant that Apple (AAPL, Fortune 500) will announce the iPhone 5 on September 12, with a release date soon after that. But if you want to offset the cost of your new phone by scoring the highest value possible for your old one, trade-in experts say you'll need to lock in your trade now -- before everyone else gets the same idea.

"We always get a rush of people who wait to get a quote until they have the new [iPhone] in their hands," said Jeff Trachsel, the chief marketing officer for trade-in serviceNextWorth. "But as the volume increases, the value of your phone declines."

Trading in now will help you avoid that rush and score more cash. Most trade-in services simply ask for you details about your device, like its storage size and condition, and offer up a price that's guaranteed for 3 weeks to a month. In turn, the companies typically refurbish and resell the devices.

Smart traders play arbitrage: Lock in a price now, then wait until you have the new phone in hand to actually send in your old model.

Old iPhones hold their value remarkably well. At NextWorth, a 16 GB iPhone 4S in good condition currently fetches $274. Rival site Gazelle is offering $277 for an AT&T phone or $260 for a Verizon or Sprint device.

Go one model older, to the iPhone 4, and you can fetch $175 at NextWorth for an AT&T phone or $162 for a Verizon phone. Gazelle will pay $160 to $165.

Click here to continue reading: http://money.cnn.com/2012/08/20/technology/iphone-trade/index.html?iid=HP_LN&hpt=te_t1