How to Invest in a Stock Market Fund

No stock index fund and certainly no individual stock can give you a guaranteed, safe, tax-free return of 16.9 or 19.9%. At 0%, I would certainly recommend doing at least a little bit of both, paying down the debt and contributing to your Vanguard account. And probably even at 2% to 3% per year, I would still do so,. The reason is that I like spreading out my equity investments over the longest possible time span.