We have had loads of problems with the little buggers. Had a pest guy some round who got rid using poison but they did come back.
I found the only way to really get rid is to make sure they cannot find any food, we now put everything in tupperware boxes. That made a dramatic affect on the nunber of times we found droppings etc.
I even put a shelf up in the kitchen which was about 10 inches from the ceiling to keep cereals etc, the buggers even managed to get up there, the only way they could have is by somehow climbing up 8 foot of smooth wall !!!
As Nostoc said, you need to make sure they cant get in, lots of chicken wire under the eaves or in any holes in walls etc.
One time we borrowed a local farms “ratter”. The spaniel spent an hour in our garden and must have killed at least a dozen mice !