If you're changing accounting firms, don't wait until the last minute to give notice to the "old" firm. A sudden switch may provoke animosity and create havoc with tax matters and other record keeping.

Mark Feinstein, president of Northeast Management, a video-rental company based in Lincoln, R.I., avoided such problems last year when he left a Big Six firm for a regional accountant. One secret: he scheduled the switch to occur when the new firm had the most time to learn his operations and to teach him its own systems.

Feinstein gave his old accounting firm fair warning that he intended to leave it. He was flexible about the timing: "Our old firm was involved in a couple of longer-term projects, so we proposed an extended crossover period. That way the new firm took over all our current tax and cash-flow jobs, and the old firm finished its projects and phased itself out."