The reason houses have gutters is so they can collect the water from the roof and move it away from the house. If the gutters are full/If they do not do this, the water will fall onto the ground and can cause the buildings foundations to erode/damage.
Cut back any overhanging tree branches to avoid gutters filling up quickly. Allowing the sun to hit the roof will also keep it dryer in the winter months, minimising mould growth etc.
Whats the weirdest thing you have found while cleaning gutters?
"We clean a lot of Pub gutters in the city, so sometimes you find some questionable items in the gutters including hair brushes, underwear the list goes on.."