Mine is mostly when it's a phone or device I'm changing...
It's always a fucking headache plenty of the time and I end up losing a lot of contacts...
Most of em genuinely don't text the new number and I leave it like that..
Transferring contacts is another issue altogether 😂😂
Changing phones is remarkable complicated. They say to download from a back up but it never installs everything to the new one. Annoying in the extreme.