This can be a fairly broad question, each situation is different and in most of these scenarios, rodents from different areas react in their own way. We do suggest leaving the device running continuously until all entrance points are sealed to keep them out. Otherwise, they will come back to a familiar area and start nesting again. However, if you do know where the entrance point from the outside is and you have the device in the kitchen, you can move the device to the outside near that entrance point and it will help keep them out.