The technician called 45 minutes in advance, so I knew exactly when he would arrive, he diagnosed the problems within about 10 minutes, then installed two new springs and two new guide wires in about 30 minutes, so the job was completely done in less than an hour. He was also very forthcoming in explaining the process and components of a garage door system, and demonstrated impeccable courtesy throughout. Precision is highly recommended, indeed, as I was very pleased.