I still remember my hubby sitting with the TV one night and looking up all sleepy as a third tuxedo cat went whizzing past him " Hey, where did HE come from?"...um, well the vet had this cat that got dropped at the door and um...
Cats just kind of make themselves at home, foodbowl/litterbox/window to sit in and all is right with the world. But each dog is kind of like adding a human kid, a whole new routine...but you can still go " Ooooh just look at that pretty face, I just couldn't resist"