This video is from more than two years ago, but it underscores the importance of being vigilant about your the details of your employer's retirement plan.  Good planning requires an understanding of the fees you're paying for any investment, but particularly for investment plans where it's easy to hide fees.

One startling case from the video:  an employee in a John Hancock-administered plan was told by the administrator that expenses amounted to .1% of assets in the plan, which would be very inexpensive.  In the employee's case, the expenses would have amounted to $404.23 in the given year.  In reality, that employee paid $14,552.26 in fees! In other words, more than 97% of the fees were hidden.