The talk about leaf blowers reminds me. . . What I found was that even with properly installed guards, they would not work if there were heavy leaves on the roof that would eventually wash onto the guards. And our house was under a canopy of old growth hardwoods so that was a common situation for me.
So I ended up on the roof with a gas blower keeping the roof clean so the water would be properly diverted when it rain. My ultimate solution was to move.
