These missed opportunities haunt older Americans who are still working. None of us gets through life without a few regrets. When it comes to money, the mistakes we make while saving for retirement are especially likely to cause us remorse. Recently, the Insured Retirement Institute asked nearly 1,000 employed Americans, ages 40 to 73, about their regrets while preparing for retirement. In particular, the institute wanted to know which things these workers wished they had done differently. Following are the missed opportunities that haunt the survey respondents. If you are still saving for retirement, use this list to make sure you do not repeat these common errors.