I think the city limit is the key factor for you.

But in another situation , i.e. MINE, where there is no limit on cats, just dogs, I know I can handle 8 cats. The few months I had 9 cats, both times, I've found it too overwhelming. The other thing is, Dad doesn't do much except play with them. (Alright, that is a big help, getting them tuckered out. ) But, if I get sicck, even jsut a 48 hour bug, I still ahve to haul myself up and feed them 3 times per day, scoop those boxes, and fill the water.

And as someone already mentioned, you have to plan for the emergencies and the old age illnesses. Last week, I had SIX pets taking pills and or eye drops. Today I just have 2, thank heavens. It was an all consuming hour long ordeal. Most of the pets have ended their course of treatment; Ruffles is no longer with us. And I am amazed at the amount of "free" time I have now that I am not dealing with her age issues. I am working hard not to add any more, as I am right at my limit now.

Hope all these ideas help.