If you have brought it up with the landlord and the landlord seems reluctant to do anything, you might want to check your lease. Pest control can be a serious issue and it can affect the property value.
Landlords want to include language in the lease agreement that allows them access to your property if there is a bed bug problem or other vermin infesting your unit. It's standard stuff for a lease.
Does that mean you can just vacate and not pay rent? Probably not. Guidelines suggest that in an extreme cases, it is excusable. That sounds like you find out at the court hearing.
Talk with your landlord. If you see mice scurrying about or find evidence of nocturnal noshing by something small, you have evidence of an infestation.
The landlord should take care of having the problem addressed. It's a pest problem.
Mice seek warm, cozy places that have access to plenty of food - namely, your walls behind cupboards. If you've seen one, you probably have more - the ones inside the walls.
I have two cats. They're all over the problem. If a mouse or bird even thinks about coming into the house, they're doomed. My back porch is where they leave their trophies.
PML of Longmont, CO