A common example is contributing too much to a Roth IRA based on your income level; the ability to contribute to a Roth IRA begins to phase out at higher income levels. Contribution limits decrease once your Modified Adjusted Gross Income (MAGI) rises above $105,000 for single filers and $167,000 for joint tax filers.
(A high rate of return, of course, will beat that, but you'll have to work for it.) Assume that inflation is an annual 3% and capital gains are 15%. If your target is a 15% return before inflation and taxes, you'll end up with 12.4% return. (If you pay 20% in capital gains taxes, you'll end up with 11.6% return.) A really good return on investment for an active investor is 15% annually. That's healthy.
For some reason, calculating rate of return is very common when someone is buying a company, but not very common for individual investors buying stocks. For dividend investors, the rate of return is the dividend yield plus capital appreciation on the shares themselves. Since we are pursuing a strategy of long-term investing independent of short-term fluctuations in share price, we are primarily focusing on dividend yield.