You may have already heard of the "Rule of 72". It seems easy enough: To figure out how many years it will take an investment to double its value, just divide 72 by the interest rate.

So if you're earning 6% APY, it'll take 72 / 6 = 12 years to double. If an investment has a 8% yield, you're looking at 72 / 8 = 9 years.

OK, so what's the problem? This seems straight-forward; why am I even writing a blog post about this?

Here's the thing: The Rule...

My name is David Beroff, and my long-term goal is the development of a new social media site called AboutTh.is. A year ago, I cut my day-job hours in half so as to have more time to focus on self-employment. Since it will be quite a while before AboutTh.is will be in a position to earn me a full-time income, I've been finding various projects to help cover my day-to-day expenses.

One of the gigs that I found was thanks to a fellow Warrior. In January, he introduced me to the owner...