If your roof doesn't have gutters, then you're missing out on one of the most important elements of a home's exterior. Gutters protect your home from water damage in two ways, by catching water from rain, snow, and other precipitation before it reaches the walls of your house, and by preventing erosion caused by runoff.
If you have a home without gutters, or have broken gutters, keeping your home safe from water damage may be difficult, as water will flow over the top of your roof and leak into your walls, floors, and ceilings since it has nowhere else to go. This can lead to mold and mildew growth on your walls, which will cause major damage over time.