Dog and cat owner here.
I'd go for one of each max for any home. Registered and desexed.
In my bit of Australia all dogs and cats must be registered, with reductions for the elderly, and animals which are desexed. Registration must be renewed each year. All cats have to be kept indoors at night 9.00.p.m until 6.00.p.m.
All property has to keep dogs securely on the property. Some LAs will fine you if your dog rushes up to fences and gates barking at passersby.
All dogs on lead except certain beaches all year round, and others depending on the time of year. There are off-leash ovals, about the size of football pitch, where dogs can be exercised all year-round ( though not when match is one, of course).
Crucially, at each of these ovals, the council provides free poo-bags, and a bin to put them at several points on the oval and beaches. Rangers occasionally swoop, with in the spot fines for an off-leash dog in the wrong area, or you if you aren't armed with poo-bags, 4 are advised.
There are still people who flout this, though not often; the level of compliance is very high, and in 6 years here, I've never seen dog shit on a pavement, though there are some lazy twunts on the ovals, and I always pick up their mutt's shit.