Something has burst, something is flooding, and they are not reading. They want a phone number large enough to tap without their glasses, an honest line about how quickly you can get there, and enough signal that you are a real business to stop them ringing the next name down.
We put your number in the header on every page, spell out your callout hours rather than saying twenty-four seven when you do not mean it, and keep the route from landing to dialling as short as possible.