You hear it all the time from ads and realtors. But this time it's actually true: there has literally never been a better time to buy a home.

According to the latest data from the National Association of Realtors, the home affordability index has now entered its third year of record highs.

The measure tracks median income against median priced homes (assuming a down payment of 20 percent of the home price and it assumes a qualifying ratio of 25 percent).

A value of 100 means that a family at median income has exactly enough income to qualify for a mortgage on a median-priced home. When it's above 100, the family has more than enough income to qualify.

And the current reading is just under 200.

But we wanted to dig in to why housing conditions in America are so ripe for buying.