I'm trying to see if there is a better way to have my SPF records using the domain opposed to using the ip address - so if the IP does happen to change - the zones don't need to be updated.
"v=spf1 +a +mx +ip4:216.38.16.18 ?all"
BECOMES
"v=spf1 a:example.com mx:example.com ?all"
Assuming I've written the SPF rule correctly.