Depreciation is a smartphone's worst enemy. A flagship phone loses about 40-50% of its value in the first year. However, you can beat the curve if you know when to sell.
The "New Release" Crash
The biggest price drops happen annually in September (for iPhones) and February/March (for Samsung S-series).
Pro Tip: Sell your phone 30 days BEFORE the expected announcement. Prices start to dip as rumors solidify and plummet the day the new model is revealed.
The Holiday Peak
Demand for used phones spikes in November and December. People are looking for affordable gifts, and the influx of "new" used phones from people who upgraded on Black Friday keeps the market moving.
The 2-Year Sweet Spot
Technologically, most phones hit a "value cliff" after 2 years. This is usually when battery health starts to dip and software updates might slow down the device. Selling at the 20-22 month mark often gets you the best "return on investment" for your next upgrade.
Avoid the "Wait and See"
If you have an old phone sitting in a drawer, sell it TODAY. It is losing value every single day it sits unused. Electronics do not age like fine wine!