Ray K wrote:
Just about every screen for use at the input of a downspout has a very
fine mesh, perhaps blocking debris as small as 1/8", even though such
small stuff would pass harmlessly through a typical 2x3" downspout. This
causes the screen to clog, preventing the gutters from draining and
causing them to overflow.

It seems a better design would be something like in kitchen sink drains
use: a large cross that blocks only the stuff big enough to potentially
cause a downstream blockage.

Thanks for your comments.

Ray

I've got mesh from HD that covers the whole gutter but little stuff gets
through and builds up and causes log jam at input to downspout. Once a
year I have to go up to clear at input but previously, I'd have to clean
the whole gutter a couple of times a year I think with any of the
devices mentioned to filter at input only, you're going to have to clear
the gutter occasionally.