If you just let your employer put your retirement savings in their default mutual fund, what you&#x27;re going to get is some product sold to the company by a money manager who is taking 2-3% of your money off the top.<p>Given how rare it is for a mutual fund to consistently return even 4% for any amount of time (seriously, if you know of one that does let me know and I&#x27;ll sign up at once - 1-2% is more typical), you end up with something that&#x27;s worth less than a basic savings account, but with a bunch of rules attached to it that prevent you from using your money when you want. Depending on the circumstances, that could be a pretty poor deal.