Electronic pest management can never establish 100% pest free zones

Despite the very disturbing and stressing sound waves coming from an electronic pest management device the vermin will still visit the area should their quest for survival force them to.
If there is something eatable close to the pest management device the pest will not hesitate to pinch the food thus showing their courage against the enemy.

So, in order to test the effectiveness of your pest management device don´t use rat poison or baited traps since it will only attract more pest from the neighbourhood looking for something to eat.
Should you however like to keep track on pest movements in your house simply look for droppings or powder with chalk at strategic places to spot any foot prints.