Or, wait til the first time one of them has a hair ball. My first experience was on New Year's Eve - yes, I did call the ER vet
Or someone decides not to eat their formerly favorite food and you start running around presenting them with special food to perk up their appetites,
Or someone regurgitates and you learn the difference between that and vomiting.
But, lots of times, years and years go by without any big issues - and I know you'll never skip a checkup for those two!