SPF
Which servers are allowed to send as you, whether the record is valid, and whether it has quietly gone past the ten lookup limit.
DKIM
Whether your mail is signed at all, which selectors are live, and whether the key length is one we would still sign with.
DMARC
Whether a policy exists, and whether it is parked at none, which looks like protection and provides none.
Alignment And Reputation
Whether SPF and DKIM line up with the domain in your From header. Most failures we see are alignment, not a missing record.