People should never need to be concerned with date formats; they shouldn't even be aware that a date has been 'formatted'. They should be able to scan some content which contains a date, and not have to stop to parse it, it should be immediately obvious.

There is no need to use easy-to-mistake formats like 2025-09-01 and 01-09-2025, developers know this is the 1st of September, but developers aren't the ones using your app. It's slow to read, and a non-zero number of those people will see that date as the 9th of Jan.

If you are presenting a date for human eyeballs use date('j M Y') aka '4 Nov 2025' . It's short, quick for the brain to parse, intuitive and unambiguous.

Anytime dates are stored use machine-readable formats like ISO8601 (2025-11-04T09:00:54+00:00) or a unix timestamp (1762246854)