How well does these work when most of the debis is pine needles?

Installed these 2 years ago......they work great with pine needles.......yes a few get caught in mesh but They don’t stay or clog......I tried dillerant type and these were the best......any gurard will catch the needles if you use guards with smaller holes they will not take in very much water.....just flows over Gutter.......I have about 30 white pine trees 50 feet tall in my front yard

I personally don't see this gutter guard being good for pine needles, however they are some of the best quality gutter guards I have seen.

I agree with your concern.

Some pine needles can get caught in the mesh but over time they will breakdown and flush through the gutter system. The fine mesh gutter guards work well keeping needles out of the mesh but over time they can become blocked with debris and/or corrode with metal mesh products.