Your attic. You might not spend much time up there, and you might not think much about what goes on up there, but there could be a multitude of issues hiding in your attic. This is why it is an ideal place to do a thermal imaging scan. That way you can find issues that might be hiding underneath the insulation.
So what kind of issues might you find? One common problem is rodents. Since they dig through the insulation, you should be able to spot a temperature difference where they have been tunneling through. Another issue that you can spot are leaks from ventilation ducts that run through the attic, spilling out hot or cold air.
Another common issue that you can find with an infrared camera in your attic is recessed lights that are incorrectly installed. Recessed lights can get very hot, and they are not supposed to be in contact with insulation, since this can be a fire hazard.