Put a number on the jobs that walked because nobody picked up
For trades and home services: work out what your missed calls are actually worth over a year, using your own close rate and average job value.
Why this number is always bigger than people expect
A missed call in a home service business is rarely a message left on voicemail. Someone with a leak calls the next number on the list, and by the time you have listened to a voicemail that does not exist, the job is booked with a competitor.
The arithmetic is unforgiving because it compounds three things at once: how many calls you miss, how many of those would have closed, and what a closed job is worth. Miss five calls a week, close half of what you quote, average $450 a job, and you are looking at roughly $58,000 a year walking to whoever answered.
When the calls are actually missed
Almost never during office hours at a desk. They are missed while you are under a sink, on a roof, driving between jobs, or at dinner. Which means "answer the phone more" is not advice anyone can act on.
The practical fixes are the ones that work while your hands are full: an immediate text back so the caller knows they were heard, an after-hours booking link, or someone else picking up when you cannot.
What to do with the number
Compare it against what it would cost to fix. If missed calls are costing $58,000 a year, an answering service at $400 a month is a straightforward decision, and so is hiring part-time office help.
The reason most people in the trades never make that comparison is that the cost of missed calls is invisible — it never appears on a P&L, because it is revenue that never existed. Putting a figure on it is most of the work.