Unix Timestamp — Convert Epoch Seconds to Readable Dates
A Unix timestamp counts seconds from the start of 1970 in UTC. It is how most systems store a moment, because it is unambiguous and easy to compare — and completely unreadable, so converting it is a constant small task when reading logs, database rows or API responses.
When it helps
The seconds-versus-milliseconds confusion alone justifies it. JavaScript works in milliseconds, most other environments in seconds, and passing one where the other is expected produces a date in 1970 or somewhere around the year 56000. Both are obviously wrong once converted and entirely invisible as raw integers. Time zone questions are the other common case: a timestamp is UTC by definition, so a date that looks a few hours off usually means something applied an offset that had already been applied.
Worth running automatically
Time bugs cluster around boundaries — the start of a month, a daylight saving transition, a leap day — which is exactly when nobody is testing. Scheduled checks that exercise date-dependent endpoints across those boundaries catch the failure at the transition rather than through a customer report. Clock drift on the host is worth watching for the same reason: an incorrect system clock invalidates every timestamp generated on it, and it drifts silently.
What you get out of it
Makes a stored moment readable, and catches the two mistakes — wrong unit, double-applied offset — that account for most timestamp bugs and are invisible until converted.