A quick answer to the when question. You need to return before your dog reaches threshold. In other words before the anxiety kicks in. Ideally along with your daily routine, if you can do the in and out and in and out all evening till you and the dog are bored silly , it will help. Also make sure you leave in and come back in unanticipated lengths of time ie 3 mins 7 mins 5 mins 10 minutes 3 minutes 15 minutes etc but always return before the dog gets anxious.