Keep your iPhone, or upgrade? Cost per month, honestly.
Every September the question comes back. Put in what the new phone costs, what yours is worth, and how long each will actually last you, and see which is cheaper per month of use.
Your numbers
The new phone
Keeping the current one
Result
Cheaper per month
Keep it
Part of Phone Kit, a free appSave your details once and all 12 tools fill themselves in. Installs to your phone, works offline, nothing leaves your device.Open Cost per month is the only fair comparison
A $1,099 phone kept for 4 years costs about $23 a month before resale. A $700 phone kept for 2 years costs $29 a month. The sticker price tells you almost nothing; the years you keep it tell you everything. This tool divides each path's net cost by the months it buys you.
Trade-in value drops every September
The week a new iPhone launches, trade-in values for the previous models fall, sometimes by $100 or more. If you are going to upgrade this year, lock the trade-in quote before the event, not after. If you are keeping the phone, the timing does not matter, but a fresh battery ($99 at Apple for most models) typically buys another year or two of good use.
What actually forces an upgrade
Losing iOS updates (security, and eventually apps that require a newer version), a battery under 80% that Apple will not replace cheaply, or a camera or feature you will use every day. "It feels slow" is usually a battery or storage problem, not a phone problem. The iPhone Storage Picker and Battery Health tools on this site cover both.
Estimates only. Trade-in values, battery prices, and resale prices change often; check Apple's trade-in page and a recent sold listing for your model before deciding. Not financial advice.