After dealing with clogged gutters again this autumn, getting gutter guards sounds like a pretty good idea. But be aware of something that can affect how well they work: their shape and the pitch at which they're installed. When you configure those correctly, you'll find that leaves rarely stick to the guard, and you don't really have clogs. But if you don't use the right configuration, you could end up with worse clogging in some cases.
You Don't Want Debris Flows to Hit a Ledge
The problem is that when solid things flow off your roof with rainwater – leaves, dirt, etc. – they may flow right off if the water flow is heavy enough. That gives the items momentum, so when the water flows into the gutter, the solid items continue moving and drop to the ground. But if the water flow is not heavy enough to sweep the items down and give them some momentum, then the solid items will hit the gutter guard while the water trickles into the gutter, and stay there. That affects water flow as the pile of solid items builds and starts blocking the gutter guard. So you don't want to have the guard installed in a way that creates a ledge that traps debris in lighter rain.
Pitched Guards Facilitate Flow
If you have flat gutter guards installed, have them tilted to match the pitch of your roof. That creates a continuous slope that helps solid items continue to move down and off the gutter guard as the water falls into the gutter. No gutter situation is going to be absolutely perfect, and there is still a risk of a damp, stubborn leaf holding onto the gutter guard. But most debris will have a much easier time rolling right off that roof and gutter guard if you keep the same angle.
Special Circumstances and Rounded Guards
There are gutter guards that are rounded like a half-moon. These are hinged guards, and you can lift the guard up by one edge and flip it over, also flipping all the debris off the guard. These have a tendency to catch debris along the raised edge farthest from the edge of the gutter, so they're better used in situations where you can easily reach them to flip them over. For example, a gutter on a sloped roof on one of those asymmetrical mid-century homes may be low enough to reach without a ladder (or at least, without a tall ladder).
Reach out to a gutter guard installation contractor to learn more.