I've had closer to 9 cats (all either strays or fostered/adopted), and the two that stayed inside their entire life managed to outlive the others by like 6 years and counting. The smart reply is absolutely to keep your pets inside.

Y'all really can't wait to see your own cats flattened on the road, huh? "But my cat is smart enough to avoid cars!" No, your cat is lucky enough to have avoided cars so far.