How our numbers work
Every figure on PhoneLifespan is computed from documented data with the formulas below — no black boxes. When a number is an estimate rather than a manufacturer promise, we say so on the page.
End-of-support dates
A phone's lifespan ends when its security updates stop — after that, new vulnerabilities go unpatched and the phone becomes progressively unsafe for banking, email, and payments.
- Official promise
Samsung, Google, OnePlus, and Nothing publish explicit update policies (e.g. “7 years of security updates”). For these phones:
end of support = release date + promised years. Each phone page links the brand's policy document. - Our estimate
Apple publishes no end dates. Its written legal commitment (UK PSTI filing) is a minimum of 5 years, but its documented track record is ~7 years of updates (the iPhone 6s and XS each got 7+). We therefore estimate
release date + 7 yearsfor iPhones, label it an estimate everywhere it appears, and state the 5-year written floor in each phone's FAQ. - Unofficially extended
Occasionally a brand keeps shipping updates afterits written promise has lapsed — the OnePlus 10 Pro's original 3-OS/4-year policy ran out in March 2026, yet it received Android 16 and continues to get patches. For these phones we track the observedwindow (community-documented), label it “unofficially extended,” and treat it as likely rather than guaranteed. An undocumented continuation never wears the same confidence as a written promise.
TrueCost
Our signature metric — what a phone really costs per month of safe ownership:
TrueCost = current street price ÷ months of support remaining
A $799 phone with 84 months left costs $9.51/month; a $450 phone with 18 months left costs $25/month. TrueCost is why a cheap phone near the end of its life can be the most expensive thing on the shelf. Once support has ended, TrueCost is undefined — we show a warning instead of a number.
Safe-to-Buy badge
- GREEN — Safe to buy: 36+ months of support remain. A full ownership cycle is covered.
- YELLOW — Buy with care: 18–35 months remain. Fine if you upgrade often or the price is right; risky as a long-term keeper.
- RED — Avoid buying: under 18 months remain (or support has ended). Buy only used, only cheap, only knowingly.
Buy-By date
The last sensible day to buy a phone: end of support − 24 months. Buy after this and you get less than two years of safe use — at that point, something newer is almost always the better deal.
Value Score (0–100)
A weighted blend of what buyers actually get per dollar:
- • 30% — performance per dollar (chipset tier ÷ street price)
- • 25% — remaining software support
- • 15% — battery capacity
- • 15% — display quality (refresh rate, brightness, resolution)
- • 15% — camera system (main sensor + real lens count; token macro lenses don't count)
The weights are deliberate: support time is weighted nearly as heavily as raw performance, because a fast phone that loses updates is a fast paperweight.
Hard rule: a RED Safe-to-Buy status caps the Value Score at 40, no matter how good the hardware-per-dollar looks. A phone we badge “Avoid buying” must never out-score a safe one — and lifespan likewise overrides the verdict in head-to-head comparisons when the two phones' Safe-to-Buy statuses differ or their TrueCost differs by more than 2×.
Data practices
- • Specs are collected from manufacturer documentation — never copied from other spec sites.
- • Every update policy links its source, with a visible “last verified” date.
- • Street prices reflect major US retailers and are re-verified monthly.
- • All analysis and verdicts are written by us, for this site.
- • Found an error? Tell us — we fix data fast, because accuracy is the entire point.