Holiday dinner's must be a ton of fun at this guy's house..............
We fly SW exclusively. We haven't paid for PreCheck, and we get odd combinations between the 2 of us every time we fly out of our home airport---about 50% of the time we both get it and about 50% of the time just I get it [and DH gets full screening]. When flying home, the percentages differ, but I usually get it about 80% of the time.
It's not worth our time and money to go through the process, if it's not necessary.