The chart is fairly simple: The color coding represents a ratio of the median home price to the average two-bedroom rent, multiplied by twelve. Thus, it roughly shows how many years it would take to buy the median home, paying an average rent. Trulia then created a basic cut off for rent-vs-buy: If it takes decades to pay off a median home price, it's harder to see your home appreciation making up for all the money you lost on maintenance fees and taxes.