My four snakes take almost no time at all. I really wish I had a few more.

The rats are another matter! I use fleece bedding, and it mostly gets changed daily or it does smell. My hairless seem to stink things up the most - not sure why. I really like interacting with rats, but they are more work than even the birds (budgies, canary, dove). I make sure the ratties get daily exercise time while cleaning and prepping their food. That requires rat-proofing the area, and clean up after they are back in the cages. They are so smart, active, and engaging - I'd feel guilty if they were stuck in racks.

Goldfish are kept out in a 300 gallon stock tank. I'm paranoid about a big aquarium bursting in the house. There is no room for one in here anyway. Very easy to maintain the stock tank outdoors. Weekly water changes are just remove the plug, and bring over the hose. I go through a lot of Prime water conditioner with a tank that size, but the fish are still cheap pets to keep. Our filtration is just aerated sponges on solar, so there is no addition to the electric bill.

Hoping to get more into inverts soon. Looking into hissing cockroaches, millipedes, and maybe a couple of tarantulas (how I'll sell the BF on the last, I've yet to figure out.)