Our little beagle is in heaven! He gets to stay outside and do his thing without the restrictions of a lead or us constantly calling him. He was 6 months old when we installed it. We didn't put out any flags or markers. We just let him roam. He has minded the beep and only been shocked when trying to follow my husband over to the neighbors yard. That happened once! We are fans! UPDATE June 2018 18 Months later Bandit is still king of his own yard! We put in some new landscaping around the house and added wiring to that area, now he can't dig or poop in the flower beds. The only times he has escaped are when we were not aware the battery was dead. Now we change it every 3 months. This also tells me he does test the fence, he is not complacent and still wants to roam. The fence is perfect!