Data methodology
This page documents how every price on SellOld is captured, labelled, and updated.
Price sources
| Source | What it means |
|---|---|
| Feed | Sent directly by a partner platform. Most reliable; refreshed on their schedule. |
| Checked | Read from a platform's public price calculator using a standard condition profile. Popular models are checked more often. |
| Estimate | Modelled from real captured quotes and typical depreciation (about 40% in the first year, 25% a year after that, adjusted by condition grade). Always labelled as an estimate on the page. |
Every price row keeps its capture date, and every price table shows when it was last updated. We keep full price history — nothing is overwritten.
Condition grading
Our questionnaire covers the superset of what every platform asks: power and calls, screen glass, display defects, body, working faults, battery health (iPhone), repair history, box and bill, and age. Each platform's published grading rules are stored as data, and your answers are mapped to each platform's own grade — so the price shown is for the grade that platform would actually assign at pickup.
Reliability data
After a sale we ask sellers two questions: did the pickup happen, and what was actually paid versus quoted. Per-platform reliability scores will be published once a platform has at least 30 surveyed pickups; sitewide scores after 500. Until then, the reliability column on the vendors page stays empty.
Corrections
Found a price that's wrong or stale? Email hello@sellold.in with the model and platform, and we'll re-check it against the platform's calculator within two working days.