I started my tax career in a national CPA firm a long time ago. What shocked me about filing taxes with this particular firm was that it was charging $250 to prepare a simple tax return. What’s the big deal? Back then, $250 got you a nice two-bedroom apartment. Today, that same apartment would run about $2,000. Get it?

So I wrote a book about how to prepare your own tax return and offered $10 workshops to the public to teach people how to do it themselves. (This was long before DIY tax software—or even PCs.) A funny thing happened. No matter how much I simplified it, most of the people at those workshops insisted on paying me to prepare their tax returns.

The world is very different now. The IRS and a variety of tax software developers have teamed up to provide free tax software designed to help about 70 percent of taxpayers file their tax returns. Yet while many people will qualify for free filing, there are still some circumstances where you’ll need to enlist the help of a tax pro.

Who should always use a tax pro?

1) People with extensive securities investments, especially when the investments are spread over different accounts, IRAs, and other retirement vehicles.

There are certain overlapping transactions that might take place in these accounts that the IRS would consider “wash sales.” No losses on those transactions would be permitted. A good tax pro would catch something like that.

Working with a qualified tax pro can also help you identify which lots of securities to sell before you sell them. This would give you the most tax-beneficial gain or loss, depending on the holding period and basis (tax cost).

2) Business owners always, always, always (did I say “Always?”) should work with a tax pro in their corner. Frankly, anyone who does not is leaving money on the table and is apt to have the business fail within the first five years. Why? Either the business will fail due to disorganized management, or it will fail due to tax problems that likely will result from messed-up payroll taxes, sales taxes, and income taxes.

Not only can a good tax pro help you with tax issues but most of us also know a lot about business management, operations, and break-even analysis. Plus, we have community contacts to help build your sales and cut your costs. We may even be able to help you get financing when your business needs it—or before.

3) Folks who want enough money on which to live when they retire. This doesn’t just include IRAs and 401(k)s, it also includes all sources of income-producing assets that will allow you to live comfortably for the 30 to 60 years after you stop working. Tax pros can help your family avoid estate and gift taxes when consulted before the transactions take place.

Tax pros are actually pretty useful people. We have knowledge, experience, and contacts.

Eva Rosenberg, EA is the publisher of TaxMama.com , where your tax questions are answered. Eva is the author of several books and ebooks, including the new edition of Small Business Taxes Made Easy. Eva teaches a tax pro course at IRSExams.com and tax courses you might enjoy at http://www.cpelink.com/teamtaxmama.