Decide on your strategy
If you are starting your retirement savings early, you can afford to be aggressive and put money into riskier funds. If your fund loses value, you have time to let it grow again. However, if you're getting close to retirement and your investments suddenly lose 40% of their value, it will have a huge negative impact on your financial comfort in retirement.

The extra burden on women
The income gap between men and women is slowly closing -- but "slowly" is the key. Women still make less than men for the same jobs. And just as saving a little early can lead to great rewards, missing out on a little income early in the savings process can create a much larger discrepancy later.

More women than men take time to raise children. This unpaid time is also time during which they probably aren't saving for retirement. They may expect that their spouse's retirement is also theirs, but divorce is so common that these expectations are often not realized.

But women can't blame retirement discrepancies solely on men's higher earning levels. Surveys have shown that women tend to invest less aggressively than men. Women tend to put their money in investments whose risks and growth patterns are not so high.

As such, their retirement funds grow more slowly and, over the course of a whole career, offer indisputable proof of the difference between high-risk and low-risk investments.

Mother Nature can also share some of the blame for this one. Women, on average, live seven years longer than men. That's an extra seven years to pay for.