It's been more than a decade since I graduated from college and moved out on my own. In that time, I've been a renter, a home buyer, and a home seller.

And despite all of the complexities that are part of the home-buying process, the most important piece of advice I'd ever received was simple: Simulate the cost of homeownership for three months before you buy.

A friend suggested that I do this when I was considering buying my first house in 2005. I was a 28-year-old single professional living in Columbus, Ohio. Friends were getting engaged, married, and moving into "grown-up" homes. And, frankly, I felt like a failure because I was still renting a one-bedroom apartment, which I viewed as akin to flushing $700 down the toilet each month.