Go ahead and get some kind of traps out. The bastard has NOT gone away if you don't see him. He's crawling around at night peeing and pooping on things, chewing up things for a nest or for food.
They really love "modern" electric wires. A lot of the insulation on wires is a corn oil based plastic. It provides absolutely no nutrition for the mice that eat it off the wires, but since the plastic smells like corn to them, they chow down on it. That's what the Toyota dealership service manager said when my mother's car wiring was destroyed. He told me that they get 2 or 3 cars a week with some level of mouse damage.
A great mouse trap during a drought is a kiddie swimming pool. I have one out with 3 or 4 inches of water for the dogs to splash around in to get cool.
During the drought this past summer, at least 2x per week, I had to fish a drowned mouse or young rat out of it. IIRC, I fished 49 mice and rats out from July through September, after 6 weeks of no rain (after 19"+ in May) had dried up most of the free standing water in the pastures. The curved edge around the top is slick and if the water surface is an inch or so below the top of the pool, they can't crawl out after they slip off the edge into the water.
Doesn't work on grown rats though. They will fall in but full grown rats are big enough to crawl out. I happened to walk outside one morning just as a FG rat managed to jump out of the pool, so I know they would fall in, but then escape.