If you go to Cancun more than once a year and you hear the dreaded announcement during flight that they’ve run out of immigration cards, do yourself a favor and procure an additional immigration card upon arrival even if you already have one. This has happened to us three times. Luckily, we always used the extra one on our next trip and always had a completed card upon arrival. Get the extra form whether you need it or not if you are planning on going more than once a year.
Spirit now offers online check in. If you are able to, print a copy of your boarding pass at your hotel if it allows. Most of the time the QR scanner works, but on one occasion, Freddy had to leave the security line to go back to the kiosk to print a boarding pass. Get the paper one as a backup just in case.