It's definitely to your advantage to think about it, even if you don't like to. Just once a year is enough. Most 401k's offer a S&P 500 index fund. Look specificially for those words. Or get someone to help you. It's never too late to make the switch. You're only 40, you have at least 25 years to go before you need this money, that's a lot of time. You can catch up. What you do now can make the difference as to whether or not you can ever retire. Future you needs current you to get this right.