It usually comes down to arithmetic rather than principle. Missed calls are a veterinary customer service problem before they are a staffing one, and a veterinary call overflow service competes directly against the cost of a fifth person at the desk.

For most three-doctor practices, the comparison is not close. A part-time CSR is a fixed cost covering a fixed shift. Call spikes are not fixed. They cluster around the lunch hour, Monday morning, and the first cold week of the season. Staffing to the peak means paying for idle hours the rest of the week, and staffing to the average leaves the peaks broken, which is exactly when the calls arrive.

Overflow coverage inverts that. You pay while the lines are saturated and nothing while they are quiet, so seasonal swings stop turning into hiring decisions. Turnover is the other half of it. A desk running permanently behind loses people, and replacing a trained CSR costs more than the missed calls ever did.