Despite having no formal training, I am often asked for investment advice. A hobby of mine, is, however, mutual funds and a wealth of reading on the topic, everything from Mutual Funds for Dummies, to Flow: The Psychology of Optimal Experience and A Random Walk Down Wall Street. What the literature, schools, and academic studies suggest is that most of your account balance will grow based on your contributions and market performance. Investment advice, in the narrow sense of picking this stock or that bond, has very little to do with your balance at retirement.
More interesting, to me anyway, is how to automate the increase deferral rate and systematically tune out the “5 Best Stocks to Buy Now” messaging we are bombarded with. Sure, everyone knows someone who got into the market at the right time, got out of the market at the right time, and even more people know people who did the opposite, and lost money, often lots of money (these stories are under-reported due to what psychologists refer to as accessibility bias or selective reporting). As many have written about, the best advice for the vast majority of people, is to ignore the hype and simply find the cheapest funds and then maximize investments in those.
And, for those who want to skip the advice and keep their own counsel, the thumb rule of 110 – age = % invested in equity mutual funds is rock solid. Spend less, save more, follow the above, and things will be ok.