Now's the best time to trade-in or sell your iPhone. Why? It's because prices are currently the highest they'll be before they decline very soon. 

MusicMagpie says here has been a 150 percent increase in Apple iPhone trade-ins since Apple's launch event, with the top traded-in iPhone being the iPhone X.

The best thing you can do is confirm a trade-in price before the announcement to ensure a high price on trade-in - although you're too late for that this time. 

Prices offered are set to fall

CompareMyMobile reckons you have four days grace following a new iPhone launch to sell or upgrade in order to get the best value.

The trade-in site says that in the week leading up to an Apple Event and in the four days following the event, the value of iPhone handsets didn't really depreciate but that subsequently prices significantly declined.

Most trade-in sites will guarantee the offer they give you for a week or two - CompareMyMobile, for example, will guarantee your iPhone trade-in price for 14 days.

MusicMagpie says that handsets could lose up to 30 percent of their value in the 24 hours following Apple's Tuesday announcement of the iPhone 11 and iPhone 11 Pro.

MusicMagpie's Jon Miller says "The iPhone X was the most traded-in device in the last 24 hours, followed by the XS Max, with the standard XS included within the top five.

“What’s interesting to see is that the iPhone XR doesn’t really make our top five, or even top 10 for that matter. The iPhone XR was a slow-burner from last year – it launched later than the flagship XS, and didn’t have the same level of features."

“However, the fact it was a cheaper option than the XS, and the XS Max, meant it quickly picked up traction. With the entry-level iPhone 11 being a cheaper option to the XS we’ll be interested to see how Apple’s brand-new phone will affect the secondhand phone market in the next few months.

Interestingly, Miller also points out that sales on older handsets could increase because Apple has discontinued higher memory sizes on the 8, 8 plus and XR.

What can you expect to get for your old iPhone?  

MusicMagpie's figures for last year's phone are quite favourable. If you trade in an iPhone X 256GB you can expect to gain £680 now. So if you go and buy this year's model it will be a more palatable £319 upgrade providing the iPhone XS retains last year's £999 price point.

However, Compare and Recycle believes that depreciation is lower on models with lower capacities if you're going to sell and upgrade year after year but interestingly higher capacity models are the best bet if you're going to keep your phone for a long time. 

MusicMagpie reckons the iPhone X has held its value higher than any other Apple model released in recent years. After six months on the market, the iPhone X had a trade-in price of £610 - a 39% deprecation rate. The iPhone XS trade-in value was only £404 after six months.

Even now the iPhone X is worth pretty much the same as the XS - £379. By contrast, the iPhone XR is valued at £421, dropping by 44 percent in a year.

We've known for some time that iPhones tend to retain value better than other handsets. Compared with Samsung devices, Apple prices remain very favourable. The last three launches of the S Series ‘Plus’ range has seen on sale prices skyrocket from £779 (S8 Plus) to £869 (S9 Plus) and £999 (S10 Plus).

Five months after launch the S8 Plus retained 52 percent, the S9 Plus 51 percent, and the latest S10 Plus just 41 percent. That's quite a drop on the recent device, possibly caused by the advent of the latest Galaxy Note 10 Series that 

The Google Pixel 3a, which was released in May, has lost a whopping 62 percent of its value, while the Huawei P30 (not P30 Pro, note) has a trade-in value of just £75, losing a massive 89 percent.

What about Apple GiveBack?

Apple also offers its own programme, called Apple GiveBack in the US, or the link here in the UK which enables you to trade in various devices (they don't have to be Apple-made) in exchange for an Apple Store Gift Card.

However, the prices quoted often don't give you as good a deal as you can find elsewhere. Rival recyclers are quick to jump on this, of course, with SellMyMobile going so far last year as to issue a price comparison chart of the contrasting prices offered for the iPhone X. As always, our advice is to shop around.