> Setting $CACHE_TTL to "months" on everything, and doing nothing else. That will break a lot. DNS isn't static; IPs regularly change as servers move, CDNs ar

> Setting $CACHE_TTL to "months" on everything, and doing nothing else. That will break a lot. DNS isn't static; IPs regularly change as servers move, CDNs are introduced/changed. Long-term caching only works on NS records because changing DNS delegations is relatively rare. NS record caching does cause problems, but they are infrequent. Caching the addresses of the actual servers will break some things within days, and most of the internet the next time each server is updated/moved/etc.