And mowing 5 acres with a small gas mower at an hourly rate made my son a relatively wealthy 11-year-old. For the first pass, I set the height to 4.5 inches, which is easy to do using the height adjustment lever. Unlike an alarming number of mower makers, Ego's height adjustment system is a thing of beauty. On the Ego, the height adjustment is plainly printed in inches. This lets you know that if you set it to 4.5 inches, your grass will be 4.5 inches high when you're done.