DNS propagation (the myth)

The wait that does not exist. Nothing spreads across the internet: a record changed at your registrar is published on the authoritative server within seconds, and dig @ns1.provider.net example.com A +noall +answer shows it there straight away. What takes hours is the expiry of the caches still holding the old answer — and that duration is no mystery: it is the TTL you published before the change. So "waiting for propagation" names a countdown you set yourself. Dressing it up as a planet-wide process costs two things: hours spent watching instead of one query that would have proved the record correct, and a migration planned around superstition rather than around a TTL lowered two days in advance.