For the last several months we have been talking about the uncertainty in the self-storage investment market, due to stock market volatility, looming interest rate hikes, a new development pipeline, and the ever-changing financing market. By most measures the self-storage rental business is reasonably steady, if not booming today. However, over the last several years the self-storage industry has been able to grow and prosper because of its ability to continue to find “bolt on” revenue streams.