Left to pile up in the gutter, decomposing leaves and debris can block downspouts and trap water. As temperatures drop and the water freezes, these blockages can lead to damage to the house as well as the gutter. To clean out your gutters in preparation for winter, wait until all the leaves have fallen from the trees, and pay special attention to safety. Always use a sturdy ladder and wear shoes with nonslip soles. The ladder should be tall enough so you don't have to stand on the top rung or overreach, both of which increase the risk of falling. Recruit an assistant who can steady the bottom of the ladder and hand up tools.