I've maxed out my IRA, have a three-month emergency fund, and have paid off all my debts. I have some remaining money to invest and don't have any short-term goals to spend it on. While my priorities might change, right now my goal is "save more money for retirement", so I'm looking at a time horizon of several decades. From my (pretty narrow) understanding of how funds work, it's almost impossible to consistently outperform the market. Can I just throw everything in the Vanguard 500 and not think about it for a few years, or is that a really, really dumb idea? I know it's generally a good idea to have a diverse portfolio and rebalance every so often, but I don't need money in the short term so I don't know if I should only focus on the long game.
My main concern is that something could come up, like five years from now I might decide to purchase a house. But I'm living off just under half my take-home pay, so I'm not hugely worried about coming up with additional money short-term.