Offer your thoughts or opinion on the input financial query or topic using your financial background.

Is it a good idea to put everything in the S&P500?
At a very high-level, the answer is yes, that's a good idea. For money that you want to invest on the scale of decades, putting money into a broad, market-based fund has historically given the best returns. Something like the Vanguard S&P 500 automatically gives you a diverse portfolio, with super low expenses. As it sounds like you understand, the near-term returns are volatile, and if you really think you might want this money in the next few years, then the stock market might not be the best choice. As a final note, as one of the comments mentioned, it makes sense to hold a broad, market-based fund for your IRA as well, if possible.