After 14 years of no-pest living, mice started showing up in my mom's place (my rental property) this spring. Without an idea of how extensive the problem was, I hired a pest control guy. He sealed entry points from outside (well, almost all of them, anyway) and set (Victor) traps. Quickly caught three or four mice and that was the last I heard about mice.
Until about three weeks ago. My mom saw another one so I reset the traps I hadn't tossed with dead mice and got a couple more. This time I used Tomcats. I think they're much easier to set than the Victors. They do seem sensitive to how much bait one uses; too much makes the trap unsteady and it snaps shut prematurely. But, properly baited, they're effective. Within a day or two, the Tomcats landed three more mice. Press the spring, mouse goes bye-bye, and the trap is re-baited and reset. Haven't heard from my mom that any more have been caught but I haven't had a chance to go and look myself.
I don't have a problem killing mice in the house. They can be quite destructive and they're filthy. We have some mice in our backyard and garage (probably hers too but no one uses it). But we also have (garter) snakes and neighborhood feral cats and we have hawks and eagles which will swoop down on mice once they're in the open. We also have a compost-heap mouse pet. I tend to leave the outside mice alone. They'll feed a predator I'm happier to have around.