I know I'm a big exception to the rule, but I work at Petco and know far more about dogs than most people. The same goes for mice, rats, and guinea pigs. I'm less familiar with hamsters and ferrets.

My reptile knowledge is growing- I was previously completely inexperienced with reptiles but having owned a ball python for about a month, I'm learning quite a bit. I am nowhere near the point where I could give anyone advice on how to care for their reptile though.

I know nothing about fish.

There are many people who work in my store who know a ton about their animal of choice and many people who think they know more than they actually do. It varies widely. But I don't think it's a generation issue. I think the main problem is that corporations like Petco are more concerned about making money than they are about educating the consumer- though I will say, since I last worked at Petco, I have become increasingly impressed with the training program new associates go through.