Even if you do a good job of saving for retirement, there are some expenses that could take a massive chunk out of your retirement savings that you aren't anticipating. Specifically, healthcare costs, investment expenses, and college expenses could consume more of your hard-earned retirement nest egg than you think.The average couple who reaches 65 years old in 2018 will need about $280,000 saved to cover healthcare expenses throughout their retirement, according to Fidelity.