Getting a new pair of nameservers doesn't always mean the provider has finished setting up your domain. For .de, DENIC checks that the servers are reachable and already answering authoritatively for the domain before accepting the change, which can catch a missing DNS zone. Would you find this useful when moving a website, or not at all?
Yeah that kind of pre-check sounds genuinely useful. It catches the classic mistake of pointing a domain at nameservers that aren't serving the zone yet. Still worth lowering the TTL a day before and querying the new nameservers directly before you switch.
That's a good point! I'd also check that MX, SPF and DKIM made it across. It's common for the website to come back fine while email breaks because a record was missed.
I'd add DNSSEC to that checklist too. A DS record left at the registrar for the old provider can cause validation failures even when the new nameservers have all the website and mail records. Cloudflare's standard migration guide covers disabling the old DNSSEC setup before the switch and enabling it again after activation, so the DNSSEC migration needs its own plan. https://developers.cloudflare.com/dns/zone-setups/full-setup/setup/