It has been my experience lately, last 10-20 years, that those that have a flag outside are the ones that served in the military. At one point, I thought it was an age thing with the younger generation not flying the flag anymore, but it goes beyond that. We have neighbors in our age group that don't either. I was brought up to fly Old Glory on Memorial Day, The 4th, and Labor Day and any other special occasion like 9-11. The only houses in our neighborhood flying the flag 9-11 were the ex military ones.