I've bought a zoo pass every year since our children were young. After one or two visits using the pass it would pay for itself. Even now that our kids are grown and our grandchildren are young enough to get in free I still buy a pass each year. For one thing it's a great way to support your local zoo and another is that the zoo is a fun and safe place to walk.
We visited the zoo Saturday morning. It was a little chilly so most of the animals were out and active. Which made the walk more interesting.
It takes us about 1 hour to cover the entire zoo as long as we don't stop too long at any exhibit. Our Jacksonville Zoo and Gardens is lovely with lots of gardens and this time of year it's decorated for Halloween.