Here's how I use index funds and a simple math rule to double my net worth every decade -- without doing anything fancy.

Use this helpful money worksheet to discuss your goals and values before you walk down the aisle. Jacob Bøtter/Flickr Have you ever asked your partner, seriously, what they'd do with $1 million?

This gives you 10 years to double your money, which means you'll need a 7.2% annual return (72/R=10 leads to R of 7.2). The Rule of 72 and Investment Fees.

There's one milestone that never loses its appeal: doubling your money. Whether it’s a retirement account, an income-focused portfolio or a long-term bet on private markets, the math behind ...

For example, if you're earning 6% on your investment, the rule of 72 says your money will double in 12 years, while the rule of 69 says it will take 11.5 years. In real life, ...