spf - why include aspmx.googlemail.com

Your current SPF record is: "v=spf1 a mx -all", which means that mail
coming from your A record (74.52.105.194) and each of the MXes on your
domain (aspmx.l.google.com and friends) "pass", and everything else
"fails".

This is a VERY bad idea! Outgoing email from Google Apps Mail DOES NOT
come out through 74.52.105.194 or the MXes, so EVERYTHING you send
through Gmail/smtp.google.com will be marked as an SPF fail!

"include:aspmx.googlemail.com" is a far better idea because it covers
all of the addresses that your outgoing mail will come from. "a mx"
covers none of them.