Delaying gratification is difficult. But when it comes to retirement savings, it pays to ignore the temptation to take an early dip -- even when Uncle Sam allows it.

Every day, situations arise (say, a sale at Coach or Best Buy) that might tempt you to borrow money from your IRA before age 59 1/2. Don't do it. The price you ultimately pay is too steep.

Take Jim, for example. He invested $2,000 in a Roth IRA seven years ago. (Jim read our 60-Second Guide to opening and investing in an IRA.) He earned the stock market's average returns, and today his balance is $3,500. When his brokerage account statement arrives, Jim doesn't see retirement dreams; he sees dollar signs. His neighbor is selling a really hot car for exactly $3,500. Jim cashes out his IRA -- both his original $2,000 contribution and his $1,500 in earnings -- so he can get behind the wheel by the weekend.

However, Jim has a problem. He still can't afford the car, even though he thought he had it covered. After paying taxes on his Roth earnings of $1,500 at his marginal tax rate (let's say that he's in the 28% tax bracket), as well as shelling out a 10% early withdrawal penalty, Jim's $3,500 Roth becomes a pipsqueak $2,900.

Had Jim been able to resist the new ride, or been able to come up with the money without touching his retirement funds, he would have been a lot better off. Had he just let his IRA ride it out for the next 30 years (at the stock market's average annual returns), it would have been worth more than 20 grand.

See? Resistance is fruitful.

There are times, however, when dipping into IRA money is the only way to get by. Perhaps you've eyed your IRA savings when facing higher education costs. Or maybe you're a first-time homebuyer who needs a loaner to cover some of your costs. Maybe your family has been sacked with catastrophic, unreimbursed medical bills that you can cover only with money earmarked for retirement. For those with limited resources, delaying retirement may be the only option.

For more information, visit our Retirement Center.

Here's further guidance on what the IRS allows.

This article was originally published by Dayana Yochim on Jan. 4, 2006. Best Buy is a Stock Advisor pick. The Fool has a disclosure policy.