Our home has many mice, a few rats and possibly a squirrel. Concerned about them chewing on wires in our two-story with brick fireplace. Should I invest in an infared camera- or is this overkill?
An infrared camera might be useful if you were trying to detect or document rodent/pest activity. If you know you already know you have mice, rats, and (maybe) a squirrel, focus on getting them out and preventing them from entering. These questions/solutions might be of some help:
- How can I get rid of a mouse in my house?
- How do I find where mice are entering my house?
- How can I figure out where squirrels are entering my attic?
Alternatively, you could contact an exterminator, who can handle the removal and entry prevention for you.
Some home improvement stores or rental businesses have a snake camera / borescope that you can rent with a light. I'd just buy one as there are cheap alternatives that connect to smart phone, or laptop via USB. If you wouldn't mind putting a ~1/2" hole in the wall, you could feed it down in the cavities to check for any signs of damage.
But agreeing with other users, I'd start at investigating where they are entering the home and try and stop them. Eliminate food sources as well to persuade them that your house isn't as inviting as it looks.