To some folks, the 1040 is just a bunch of lines and numbers. But to others, the much-maligned 1040 tax form is a veritable roadmap to retirement.

Yes, experts say those with an eye for detail and a wee bit of patience can find all sorts of treasures when traveling along Route 1040.

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"Just about every line on the 1040 provides opportunities for us to pinpoint areas where we can sharpen our financial plan and set the right course for retirement and beyond," says John Diehl, vice president with The Hartford.

Here's a line-by-line look at some of the more important numbers and issues Diehl and others say preretirees and retirees should consider when doing their taxes this and in future years:

Line 7 — Wages, salaries, tips, etc.

Every trip has a starting point. And this trip begins with line 7, says Edward Smith, a tax partner BDO Seidman in Boston. This line offers the wages — typically the income, after withholding — that a family lives on, he says.

For his part, Diehl says preretirees should use this number, as well as other income figures, to develop a "retirement income plan." For starters, they need to figure out how they will replace the income on line 7 and other income lines during retirement, and what percent of that income they will need to replace.

Often, experts say retirees need only 70% to 80% of their pre-retirement income. But Rande Spiegleman, vice president of financial planning at the Schwab Center for Investment Research, is in the camp that says it's probably better to assume you'll need 100% of your pre-retirement income.

Of course, how much income you truly need in retirement is a function of how much you spend or plan to spend in retirement. "People don't have a grasp of how much they spend," says Diehl. "People need to take an inventory of expenses and income and sources of income because oftentimes there's a mismatch."

Line 8a and 8b — Interest

This line captures taxable and tax-exempt interest income. Smith suggests using the number on this line to determine whether your fixed-income investments are generating enough income. The average six-month CD now has a current yield of 4.16%, while the 10-year Treasury has a current yield of 4.73%. If your fixed-investments are generating lower returns than that it might make sense to make some adjustments.

Line 9 — Dividends

This line captures ordinary and qualified dividends. Again, Smith says this line offers taxpayers a good chance to evaluate whether their portfolio is generating enough in the way of dividend income and the right kind of dividend income.

The Standard & Poor's 500 index, for instance, has a current yield of 1.69%. Dividend yields below that might be examined. What's more, Diehl says taxpayers may want to shift their assets away from those that produce ordinary dividends to those that produce qualified dividends. Qualified dividends are taxed at lower rates (5% or 15% depending on tax bracket), while ordinary dividends are taxed at ordinary income tax rates.

Diehl says preretirees who don't rely on this income to meet living expenses might consider shifting some or all of these assets into tax-deferred vehicles such as municipal bonds. "People tend to collect investments," says Diehl. "And sometimes income has happened without rhyme or reason. People should question whether they should be paying taxes if they are not using the income."

Line 12 — Business Income

Smith says this line represents Schedule C business income generated from a proprietorship. "From this line one could consider if the business could, in the future, be sold or run by non-owner management for the benefit of the owner for retirement purposes or other," Smith says.

In addition, Diehl says taxpayers with Line 12 income should consider some of the new types of retirement accounts, such as solo 401(k)s and solo defined benefit plans, that allow taxpayers to save more money than in traditional retirement plans highlighted on Lines 28, such as SEP IRAs and SIMPLE IRAs.

Line 15 — IRA distributions, line 16 — Pensions and Annuities, and Line 20 — Social Security Benefits

Preretirees will need to get a sense of where their retirement income will come from. And Diehl says retirees need to evaluate whether they are taking income in the most tax efficient way. For his part, Smith says taxpayers should ask whether income on these will continue for the duration of retirement.

And taxpayers under age 701/2, who are not presently taking required minimum distributions from their IRA, should factor in that income when doing cash flow planning and budgets. Taxpayers who have inherited IRAs will also need to make sure they take any required distributions from those accounts.

Line 17 — Rental real estate

Smith says taxpayers should crunch the numbers on their rental property and ask some tough questions, chief among them: "Can this property continue to be rented to provide rental income or should it be sold and the proceeds reinvested to aid in retirement planning?"

Line 18 — Farms, partnerships, subchapter S corps and trusts

Smith says questions here include: Can the business continue to be run to provide retirement income? Is there a succession plan in place? Would a sale and reinvestment of the proceeds generate greater returns? Do you need liquidity?

Lines 32 — IRA deduction

Diehl says taxpayers might consider these the save, save, save lines. Line 32 asks whether you contributed to an IRA last year.

"Investors should be taking advantage and contributing as much as possible to government and employer-sponsored tax-deferred retirement vehicles such as 401(k)s, IRAs and 403(b)s," he says. "And if you've taken full advantage of these plans, you might consider other tax-advantaged savings vehicles."

Meanwhile, Bernie Kent, co-author of "PriceWaterhouseCoopers Guide to Tax and Financial Planning 2006," says taxpayers who don't qualify to make a deductible contribution to an IRA should consider making a nondeductible contribution.

"If your income is too high, this will be the only type of IRA contribution you are allowed," says Kent. To answer the question, he says you will have to consider these factors: how the IRA is to be invested; current and future tax rates on ordinary income and capital gains; whether the lower capital gains and dividend tax rates will be continued after 2008 and your expected date of withdrawal.

"For some taxpayers the nondeductible IRA is good because it creates tax-deferred retirement savings," Kent said. "Other taxpayers would rather invest outside of the IRA and receive long-term capital gain."

Also of note, Kent says taxpayers who are searching for the form on which to report their Roth IRA contribution should stop looking. "Surprisingly, the annual Roth IRA contribution is not reported anywhere on the tax return," he says.

Lines 27, 28 and 29

Diehl calls these the small business, big opportunity lines. Self-employed filers need to be aware of the vast number of retirement plans now available for small-business owners, and take full advantage of those plans for the benefit and that of their employees.

Schedule A: Real estate taxes

Smith says taxpayers can use this number to get a sense of the assessed value of their residence and other parcels. In addition, he says taxpayers might consider this number (if they downsize their home) a source of future investment funds to generate retirement income.

Schedule A: Mortgage interest

Smith says this number gives the taxpayer a sense of the debt on real estate that would be paid upon sale of a residence.

Robert Powell is editor of Retirement Weekly — a service MarketWatch, author "20 Tips for Retirement Investors," and co-author of "Decoding Wall Street." He is also developing two personal finance series for public television.

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