Even after my move, I still consider my home zoos the ones in Buffalo and Rochester, NY. For the Buffalo Zoo, when I was a member, I would be there at least once a week, if not more. I would spend at least two hours there per visit, but they consisted more of 3-4 hours. I find with small zoos like Buffalo and Maryland, in this time frame when you have seen it all, you can keep going back to a certain animal to see if they are doing anything different. For Seneca Park Zoo, it only takes me a couple of hours since it is so small.
For my now "local" zoos, as mentioned I spend a view hours at the Maryland Zoo and revisit areas. For Smithsonian National Zoo, I have been known to only spend a couple hours there, but that's only if I plan to do other things in the city or due to timing and trying to avoid rush hour. But to throughly see it all and be at my own pace, that zoo can take me four hours or more. For both of these zoos, I only visit once every couple to a few months. It's quite a change having the previous opportunity to visit Buffalo Zoo whenever I wanted. It definitely makes the visit more special, but it also makes me want to visit a zoo every day off I get, which I know is not always possible.