Nah man Rule of 72 rocks the casbah. It's not too hard to understand and it totally rocks your world once you see how it can apply to just about anything, not just investments (like a bank vs a cd) but anything else that works on a percentage: loans, debt, rate of inflation, etc.
My first encounter with rule of 72 (though I didn't know what it was called) was behind this math question which I think is a popular one sprung on people in middle school:
Of the below, which comes out to the higher dollar amount
1) Someone give you $1000 on day 1, $2000 on day 2, $3000 on day 3, etc.. for 30 days?
2) Someone give you a penny ($.01) on day 1, and then double it each day. $.02 on day 2, $.04 on day 3, etc.. for 30 days?
And so not to totally hijack this thread, Tyler Lockett's awesomeness will increase each week by 2%
