Why do gutters clog?
Apart from the debris which finds its way into the gutters, the major components of any gutter system is the size of the outlet or drain. A small opening will dam with debris much quicker than a larger one. Large leaves will quickly clog any system.
What damage can be done?
Over flowing gutters can literally be carrying over a ton of water on a typical home, straining the fasteners and gradually causing them to loosen. Water damage to the structure, potential leaks into the home, rot and mildew are good reasons to maintain your gutter system.