If you were anything like me this past year, you'll be making your IRA contribution for tax year 2010 in April 2011, nearly a year from now. That's perfectly fine; the deadline for 2010 contributions is Apr. 15, 2011, not Dec. 31, 2010. In fact, according to Fidelity Investments, some 45% of Americans make their contributions at the last minute. But there's a good reason to not put off giving money to your IRA.

If you make your contribution now, your money will have an extra year in which to grow -- and that time could make a big difference. Witness the examples of the following stocks from 20 years ago, which shared some of the traits that can signal the best stocks for IRAs.

Over the past 20 years, Lowe's (NYSE: LOW) has grown from a small regional home-improvement chain to the No. 2 player in the industry, thanks in no small part to the favorable conditions that supported the housing boom during much of that time. With signs of life in the real estate market now beginning to return, Lowe's stock could be worth examining again. Lowe's 20-year performance of 18.4% annually was enough to turn a modest $5,000 investment into $151,700. But an extra 12 months of growth would have yielded $213,800 -- a $62,100 difference!

Walgreen (NYSE: WAG) is another strong long-term performer. It has expanded the scope of its business over the years, moving deeper into areas as diverse as pharmacy benefit management and grocery goods. A $5,000 investment in Walgreen 20 years ago would have grown at an annual average of 15.3%, turning into $83,800. An additional year of growth at that rate would add up to $94,400, giving you an extra $10,600.

And what if you lucked out and invested in a lollapalooza long-term performer? EMC (NYSE: EMC) has averaged 30% gains annually over the past two decades, partly by competing in an industry that was experiencing explosive growth. As companies create more and more data, they need better and more innovative storage and information-sharing solutions. At 30% a year, your $5,000 investment in EMC would give you an extra $340,000 over a single year!

Even slower-growing money, invested in the overall market via an S&P 500 index fund or a similar passive investment, would have made the most of an extra year's growth. When it comes to investing, time can play a critical role.

Then again…
Of course, there are some scenarios in which you might not want to make your IRA contribution now. Not everyone can contribute the maximum -- $5,000 for those under 50, and $6,000 for those 50 or older. Some people will have their maximums reduced if their adjusted gross income tops a certain level, and some people with high incomes may not be permitted to contribute at all. Most of us know or can easily figure out how much we can contribute. But if you're not sure where your income will end up at the end of the year, consider making just a partial contribution now, or simply waiting until next year. 

However much you're allowed to contribute, you'd be wise (and Foolish) to chip in no less. Fidelity data shows that for tax year 2009, the average sum plunked into a Fidelity IRA was close to $3,200. Meager contributions can lead to lousy retirements.

Dividend payers make good IRA holdings. Jordan DiPietro describes "The Best Dividend Stock. Period."