Apple will hold its feverishly-anticipated September 9 event, where it's tipped to , , and .

With the Apple Event underway, which was teased with the tagline It's Glowtime — presumably hinting at the glowing new animation , we expect two things to happen. First, from its lineup.

And then, the trade-in value of the iPhone in your pocket will plummet.

Yes, if you're thinking about selling or trading-in your current iPhone to fund the purchase of the latest handsets — you should act fast. That's because experts have warned the value of older iPhones drops by 9% on average following the announcment of a new model from Apple. This annual depreciation trend has led to a 28% increase in searches for "iPhone trade-in" in the UK this month, according to data from Compare and Recycle.

According to data shared with GBN from Compare and Recycle, which compares rates from some of the most popular trade-in providers, including the likes of , , and , this is what we can expect to happen after in a few hours:

This depreciation trend has intensified in recent years. The iPhone 13 series lost 40.09% of its value in the first year, while the iPhone 14 lineup depreciated by 47.80%.

Most strikingly, the iPhone 15 series lost 55.57% of its value on average in its first year — the first iPhone to lose over half its value within 12 months, experts warn.

Data from Compare And Recycle, a price comparison service for some of the most prominent trade-in services in the UK, showing the dramatic depreciation of previous iPhone models

Based on the depreciation rates of recent iPhone generations, Compare and Recycle predicts that certain iPhone 16 models could lose at least 60% of their value within 12 months.

Experts at Compare and Recycle told GB News: "Based on our historical data, trade-in prices are traditionally at their highest during August and early September, making it the best time to sell your iPhone. So, if you have your heart set on getting the iPhone 16 in a couple of weeks, it’s best to trade it in sooner rather than later.

"If you’re in no rush to upgrade, don’t panic, as during the second year after release, iPhones reach a plateau and depreciate much slower than in the years before and after."

A new trend has emerged in iPhone depreciation rates — the Pro-grade models are depreciating slower than the non-Pro counterparts released the same year. This suggests purchasing the pricier Pro model could be a wise choice for those keen to maintain their device's value over time.

However, avoid the maxed-out models with 1TB of built-in storage — these retain the least value.