Uhmmmm...just want to say that if you have seen ONE mouse in your house, chances are REALLY good that you actually have dozens living in the structure. Or HAD, anyway. Mice breed ridiculously fast, and one means LOTS live there.
Before I got cats, we had severe
mouse infestation, and I would find droppings all over my kitchen, in drawers, in the cabinets, bleah!
My Ginger caught just one, last March, and it squeaked and squeaked and squeaked its little heart out as I let her play with it, figuring it's teensy little screams for help might just warn the other mice that hanging out at my place probably isn't such a good idea anymore.
I don't find droppings anywhere anymore - I think the mouse family took the hint and moved on, after their little family member didn't come home that night they heard it squeaking in terror. We haven't seen any traces of them since.