Over the years of seeing thousands of houses with ever kind of gutter guards there is, these are the kind that I recommend to my customers, I like these because not only does it help your gutters not to clog up so quickly, but it also helps prevent any debris from going in any underground pipes you might have. I do stress though that no gutter guard is an absolute fix. what gutter guards do in many situations is help your gutters still drain between cleanings. Regular cleanings are still important to not only clean the guards but also your roof, behind chimneys and also around your roof vents.
We install 5"or 6" black or silver perforated aluminum gutter guards that are screwed in and cut to fit.