1. A good reply takes time to write
An enquiry comes in during the evening, or while you're out on a job. Writing a proper reply from scratch takes time you haven't got, so it waits until you're back at your desk. By then they may well have asked someone else too.
The writing doesn't have to be the slow part. A reply in your tone can be drafted as soon as the enquiry lands, so all you do is read it and approve it.
