I use the same stretch to help ward off back and hip tightness. Usually the last thing I do before leaving the gym, plus a few times at home in the evening when it gets tight. Morning would probably be good too, so you're not walking around tightened up all day.
Another stretch I like is to take a length of rope and make a stirrup for one foot while lying down - you can raise that leg and stretch the hamstring, pulling it straight towards the head or slightly across the body, then bring it across (leg still extended) until foot hits the floor. I'm sure there's a name for this but I don't know it - just feels good on the hip to torque it across and hold it there for a while. But I suck at flexibility, so what do I know.