seriously mice are bad. i live in one of the nicest buildings in downtown sf and two years ago we got mice. it went from seeing a baby mouse crossing my living room to hearing them eating at night. i put all kinds of glue traps out and they had the exterminator in the building but it was still a couple months before they were all gone. meanwhile they did all sorts of nasty things like crawl in the bottom of the sofas, in the kitchen drawers etc.. craping and pissing everywhere. i just threw a ton of stuff away and got all new furniture. id do something quick. if you see one theres 100 you dont see. i know i wouldnt want to breathe the air from an air conditioner that had had mice in it. in my building they somehow traveled from condo to condo through the heaters so you definitely need the cooperation of the entire building to get rid of them.