I'm told that stuffing entry points with steel wool is a good deterrent. Supposedly mice get very annoyed at its presence and abandon their efforts.

We seal every hole we find, they still get in. I have accepted that i need to trap spring and fall. Mansfield supply carries the best snap traps (grey plastic with red letters, "better mouse trap" or something like that). I've figured out most of their runways so set thr traps there.

We did that! Then put in spray foam over top. Fingers crossed!