Before the year end, and preferably not in the last fortnight of it. Almost everything that works — pension contributions, equipment timing, dividend timing, salary levels, capital gains harvesting, ownership changes — has to happen before 5 April, or your company’s year end, to affect that year. Once the year is closed, we are recording history, and the conversation shrinks to making sure nothing is missed. This is the difference between an accountant who saves you money and one who reports what happened. The other honest answer is: at the moments when something changes. Taking on staff, crossing the VAT threshold, buying a property, selling the business, having a very good or very bad year — those are the points where a conversation is worth far more than an annual review.