Gutters have an important job: to protect your home from water damage. However, they can’t do that when they’re overflowing with dirt and debris.
Throughout the days and weeks, your gutters are collecting all sorts of stuff, including leaves, dirt, and sticks. Over time, these materials block the flow of water. Instead of moving down the gutters toward the downspout, the debris forces the water over the edges of the gutters and down the sides of your home or other building. That water can cause serious and expensive damage to your roof, siding, and foundation as well as the soil and landscaping features in your yard.
That’s only part of the problem. The build-up of debris creates an excellent home environment for all sorts of pests, including rats, squirrels, mosquitos, spiders, and other bugs. The weight of the rodents and the debris can cause the gutters to fall off your house. That would actually be almost a good thing—otherwise, those dirty gutters just stay up there accumulating more gunk, and they get messier and moldier (and more populated by rodents) every day.