Just read right through this thread, as we now have mice in the house. DH came down in the middle of night to find a mouse running over the worktop and leaping into the toaster, where he obviously found the tray of crumbs. He was quickly put out, and we now have absolutely no food lying around e.g. fruit bowl (mouse loved the plums!), toaster. Bought humane traps last week, and, having primed them with chocolate, so far have caught three mice. Box advised taking them at least a quarter of a mile away, so DH gets in the car each morning to take them to a nearby graveyard. Building work going on to extension to side of existing house, and now weather colder mice obviously getting in to enjoy benefits of excellent insulation, but apart from the first little beast, none now go farther than the cupboard under the sink, where the trap is located.
Years ago, in another house, our four cats brought fieldmice in through the cat flap at least once every night, they were rarely eaten but just played with and then forgotten. I'd often come down in the morning to find a mouse sitting shell-shocked in the middle of the floor - and they didn't half bite when we went to release them into safety! Sadly no cats now, but we are seriously considering getting one before the winter sets in.
Son scornful, advised "doing the job properly" and killing mice outright, but at the moment we don't feel like doing this.