The practice calendar decides everything
Accounting firms do not have a smooth year. There are weeks when the entire team is filing, and there are weeks when there is room to take on work. New business arrives without regard to that calendar, and the usual result is that enquiries received during a crunch are answered late, badly or not at all, while enquiries received in a quiet fortnight get a partner on the phone within the hour.
The fix is not to work harder in the crunch. It is to separate the fast part from the slow part. First response stays fast all year, because that is what stops an enquirer approaching another firm. The scoping call and the proposal can be scheduled honestly into the following fortnight, and prospective clients accept that readily when a firm explains it, because a firm that is visibly busy with statutory deadlines is a firm that takes deadlines seriously.