My wife and I some time ago came to conclusive agreement on the ideal total number (3) and exact configuration (2 feline, 1 canine) of pets. We actually had this particular set-up going for a while, but only for a while as our second cat succumbed to sudden illness. Soon thereafter we rescued our second dog, which respected the right pet population cap but inverse-optimal arrangement of species. At the time we thought both dogs would appreciate having a playmate, only to learn in time that they drive each other crazy. Meanwhile our lone cat (really my wife's cat, predating our dating) seems to enjoy her solitary station anyway. It's difficult, in hindsight, to pinpoint specifically if we codified the 3 max, 2 cats, 1 dog formulation before or after the back-up dog was adopted, but if we didn't I can be fairly certain that accord was reached shortly thereafter at the latest.
So hey, did I mention that we rescued a kitten? Because we totally did. Also, did I mention that we got rid of any of the other pets? Of course not, because we absolutely didn't. So we now somehow have 2 cats and 2 dogs, and it's still too early to tell how all of their inter-bestial personality dynamics are going to work out because the kitten is very tiny and frail and confined to a large dog crate day and night (as much to prevent the itty little thing from getting lost down an air duct as to keep the overly inquisitive dogs and skeptical cat from messing with him). But of course the little guy adores the latest pet to join the family. Finally, after four months of being told that he can hug and kiss his baby sister but that's about it, there is another tiny creature in the house which he is actually permitted to pick up in his arms and carry around. Good times.