Changing nameservers can take up to 48 hours. Things usually settle down after the first few hours, but a few odd users will continue to be directed to the old

Changing nameservers can take up to 48 hours. Things usually settle down after the first few hours, but a few odd users will continue to be directed to the old nameservers well into the next day. This is exactly the kind of intermittent, hard-to-diagnose issue that you don't want to have to worry about in the middle of a crisis such as "Digital Ocean killed my company." Changing A records, on the other hand, can take as little time as you want depending on the TTL value.