A word -- actually, three words -- of warning about accelerating some tax payments: alternative minimum tax. This parallel tax system was devised in 1969 to guarantee that wealthy filers paid their fair share to the IRS. But nowadays, literally millions of middle-class filers are finding the AMT applies to them.

 There are a couple of reasons so many taxpayers now potentially face the AMT. First, the parallel tax system isn't indexed for inflation. Without that annual adjustment, regular income increases have pushed many filers, particularly those in high-tax states such as New York and California, close to or into the earnings level where the AMT kicks in. So annually for the last few years, lawmakers have increased the income amount that is exempt from the AMT.

 Second, under the AMT, some usually acceptable tax breaks aren't allowed. Mortgage interest on your main and second home is still AMT-deductible, but home equity loan interest could be disallowed. And real estate and personal property taxes aren't deductible under the AMT. So before you shift payment of those taxes into this year, make sure you won't face an AMT bill where the write-offs won't be of any tax use.

 And remember: While an early payment will give you 13 mortgage interest amounts to deduct this year, it means that the next tax year you'll only have 11 -- or 12 if you pay a little early next December, too. So before you send off that check, make sure you really need the added tax deduction amount on this coming return.