Over the past 40 years, I've seen so many changes in the real estate investing business. The only constant in this world is change. You've got to be prepared and know your history of the market so you don't repeat what happened before. Yes, the economy is a big factor. But the mentality of investors also plays a huge role. If you track the economy over the past 40 years, you'll see how many economy changes we've had that greatly impacted the real estate industry.