http://y7egb5vi45k74makeixpfb7jnimfxm3gf233lb3ke2ldonozjk55nvad.onion/notes_on_dns.html
This trade off is
controlled by the owner of the DNS record through a “Time to Live”
feature, where how long the record should be cached is set. A typical
time is an hour, but as long as week might be used. You might be shocked
at this value, but, should a server go down, having your DNS record
cached at all major ISPs as one value, when your IP address has changed
to a new value, might be quite frustrating.