We've been in our home for about 5 years now, but we bought down the interest rate as far as we could so our break-even point is still a year or so out, not counting appreciation. Our realtor told us over and over again than if there was any doubt we'd be in the house for 5 years we would very likely lose money selling it.

There will always be people who break even after 15 years, just like there will be people who hit the lottery and sell for 5x while the ink on their mortgage application is still wet. But 5-ish years on a standard 20% down no points 30 year mortgage seems like a good rule of thumb outside of VHCOL areas.