1. For most small and midsized businesses, the new calendar year is also the beginning of your new fiscal year. The cutoff between old and new accounting software is clear, and the break is clean, says Amy Levy, software analyst for Boston-based Summit Strategies. "Switching in the middle of the year or, say, November, can mean a messier transition," she says. (If your fiscal year doesn't match the calendar year, see below.)

2. You will spend less money on the transition. If you choose a Microsoft Business Solutions product, for example, your reseller will help with implementation and service. But your involvement of accountants or consultants is likely to be minimal, compared with a midyear switch, says Jack Deeds, owner of Washington, D.C.-based Good Deeds Accounting Software.

3. Migration of data will be minimal. Migrating your data from QuickBooks and Microsoft Business Solutions' own legacy accounting software programs to Small Business Financials or other MBS financial-management solutions is relatively easy, to be sure. But if you are moving over at the beginning of the new year, you shouldn't have to worry about migrating data at all. Beyond entering new beginning balances by hand, you simply begin filling a new database. No gaps to worry about covering if you have your system is up and running by Jan. 1.

4. A complete year's worth of "drill-down" information. Microsoft Business Solutions products such as Small Business Financials feature true double-entry accounting and a secure audit trail that allows you to "drill down" on a transaction right to the source documents. Such features aid in developing financial statements or reports that can be audited and shown for external use. Many small-business accounting packages do not offer the "drill-down" capability; you also lose it if you have to enter data by hand during midyear transitional periods, says Deeds.

5. Overlap in using two systems should be minimal. Granted, you can't get rid of your old accounting system for at least a month or more, as you finish off your year-end reports and complete business tax and payroll tax obligations. But the overlap will be much shorter and more manageable.

6. You can adjust to tax law and other changes right off the bat. That goes for all accounting changes, payroll changes and anything else your business does differently in the new year.

7. New year, new budget, chance to break old habits. If you are implementing some new budget initiatives for your company, you have more incentive to track them, follow them . . . and keep them.