A good greeting does four things in under 20 seconds: says your name, says what to leave, says when you’ll call back, and tells someone with an emergency what to do. These are written for trades, where the last one matters.
While you're on a job
“Thanks for calling Reno Rooter. We're out on a job and can't pick up right now. Leave your name, number, address and what's going on, and we'll call you back today.”
Name first, then exactly what to leave, then when you'll call. About 11 seconds.
After hours
“Thanks for calling Reno Rooter. We're closed for the night. If you smell gas, leave the house and call 911. Leave your name, number and what's going on, and we'll call you back first thing in the morning. If it's an emergency, say so at the start of your message.”
The safety line comes before the instructions, where a frightened caller hears it.
Short
“You've reached Reno Rooter. Leave your name, number and what you need, and we'll call you back today.”
Seven seconds. Callers who already know you don't need more.
Holiday
“Thanks for calling Reno Rooter. We're closed for the holiday and back on Monday the 30th. Leave your name, number and what's going on, and we'll call you back that morning.”
Say the day you're back, not just that you're closed.
Heating and air, in season
“Thanks for calling Desert Air. We're with other customers right now. Leave your name, address and whether your system is blowing warm air or not running at all, and we'll call you back within the hour.”
Asking the one question that sorts urgent from routine saves the callback.
Electrical
“Thanks for calling Volt Electric. If you see sparks or smell burning, get everyone out and call 911. Otherwise leave your name, number and what's happening, and we'll call you back today.”
Tells a caller in danger what to do before asking them for anything.