The roof of your home represents a large area that collects rain. Anything that falls on it needs to be collected and carried away. Gutters and downspouts are the transport system and when they are functioning correctly the water that falls on the roof flows through the gutters off the roof and into the ground. However, debris in gutters can clog that flow and cause gutters to stop working. Since it is not very easy to see inside your gutters those  obstructions can often go unnoticed. By ensuring that water flows freely from the roof gutter guards help keep debris out of your gutters which allows the rain to flow freely to your downspouts and away from your home.