Well, I’m not an electrnctian, but, I work in a similar trade. Generally when customers ask this question the answer is because I had 4 customers before you, and one of them talked the entire time I was trying to work, and another I did a complete renovation of the system. Often times, it makes way more sense to finish what you started than to stay “on schedule”. Which is why there are appointment windows generally. Trust me, all we want to do it go home and your appointment is what’s between me and that goal. We don’t want to take anymore time than we have to.