All gutter guards clog. But hold on. Whereas all of them clog requiring maintenance, one is easy with which to maintain.
First, the terms gutter covers, gutter guards, gutter protectors, and leaf guards are basically interchangeable. Some companies advertise screens as gutter guards and that's just a misnomer as leaf guards all characteristically all have a solid top surface.
Basically there are six different types of devices:
1. Screens. There are many different types-flat with all types of openings (round, square, louvers...) made of plastic, wire, and metal. Some disguise themselves with steps in the screening and one even has troughs in it.
2. Filters, membranes, and brushes installed on or in existing gutters--they call themselves leaf guards.
3. Flat solid top with rounded front nose--fin type leaf guards. And there's one in which in addition to the fin also has small openings on the top--basically a screen in conjunction with a fin)
4. Flat solid top with rounded front nose and a trough--fin type with trough.
5. Rain dispersal and the flipping type of gutters. One (not yet on the market) that makes a larger than life opening in the gutter for larger than life downspout attachment. The homeowner has to remove downspouts from house to clean--more joy for the homeowner (a gutter full of muck coming down upon him.
6. Flat solid top with rounded front nose and a double row louvered front vertical surface to collect water.
Of approximately 100 different gutter cover/screen/filter products to choose from all but one fit in the first five categories.
For the record, all screens (the first type) clog. To maintain them, one has to ascend a ladder to clean the screen and the gutter beneath the screen because dried debris on top of the screen is often pummeled into the gutter by rain water. This maintenance is often more work than just cleaning the gutters would have been. One screen clamps to the front gutter lip, is made of vinyl, disguises itself with steps and troughs, but basically it's a screen and is nearly impossible to remove without destroying the gutter when if fails.
The second type (filters) is either a filter installed in what is otherwise a solid top surface or some kind of filter or filament or brush installed inside the gutter. Again it doesn't take an MIT graduate to look into the future and see what will happen--debris will gradually accumulate on the filter, filament or brush. Experience shows that after two years at most, this debris solidifies resulting in clogging the gutter. The brush-in-the gutter system recognizes this and suggests removing the brush from the gutter periodically to clean them--can you imagine the fun in that--slop all over the roofing, siding and windows?
There are a dozen or so of the fin type leaf guards (the third type). They are either covers installed on top of gutters or the all-in-one leaf guards to replace existing gutters. Patents have expired and the field has exploded with many variations of this style. The rain water sticks to the rounded surface and flows downward into the gutter. Years of experience shows that in addition to water, sufficient tree debris adheres to the surface in mild-to-heavy debris conditions to clog the gutter.
Maintenance can only be done by ascending a ladder, removing sections of the leaf guard and cleaning the gutter and downspout--not a pleasant task for the homeowner who is often at the mercy of the installing company to render service. Because some of these protectors are nailed into the roofing, the roof is in double jeopardy of developing a leak when they are replaced from being cleaned. In the case of the all-in-one leaf guard, the gutter must be flushed. Larger than life downspouts are used to accommodate this flushing, but it still requires someone to ascend a ladder to do the dirty dangerous job.
To rectify the design deficiency in the fin type, two types of hybrid covers have been developed:
1. A fin type with small openings on the top solid surface--basically a screen in combination with fin. It too is subject to the same problems screens face plus the fin type which eventually clogs the gutter.
2. The fourth type (which in addition to having a fin) contains a trough with sieve openings. It doesn't take an MIT graduate to see that the same amount of debris that flows over the fin will also enter the trough where either the sieve openings in the trough clogs or enough debris passes the sieve openings to clog the gutter. Again, servicing is a big problem.
The fifth category has nothing to do with protecting existing gutters but instead replacing them with a dispersal system which clogs with debris on top and doesn't work in light-to-medium rain fall conditions and replacement gutters that are cleaned by flipping them or using telescopic pressure system to clean gutters--messy and dirty chores for the homeowner.
The third and fourth type of guards are in the right direction but they don't limit the size of the debris that the fin collects. Wouldn't it be nice to limit the size of debris? Wouldn't it be great to have two rows of interspersed louvers that deliver the water into the gutter and limit the size of debris that enters the gutter?
While all leaf guards clog would it not also be great if the gutter inside never clogged even after twenty plus years; and louvers that might clog in heavy debris conditions be visible from the ground and be easily maintained from the ground by using a telescopic pole and brush? And wouldn't it be great if this were not a dirty job but one that could be referred to as "suit and tie" maintenance if it every had to be done? The sixth type of gutter protector is the answer.
In reality, to tell anyone who has to clean his gutters more than twice in the Fall that a guard will never need servicing is like asking him to believe in Santa Claus.