The calls you miss on the job are booking with your competitor.

A homeowner just found a burst pipe. She's searching for help and calling down the list. The first company that gets back to her usually gets the job. Not the biggest one. Not the cheapest one. The first one. If your phone goes to voicemail while you're under a sink across town, and nobody calls back until morning, she's already booked someone else. You didn't lose that job because of your work. You lost it because of timing.