Once a year is a good starting point
For many homes, an annual check is enough. If the house sits under trees or the roof sheds a lot of moss, the gutters can fill much faster and may need a second visit.
Signs they need attention
Look out for water pouring over the edge, plants growing from the gutter, stains on the wall below or visible moss around an outlet.
When should they be cleaned?
After the autumn leaves have fallen is a popular time, before winter brings more heavy rain. The best timing really depends on the trees and roof around your home.
A clean will not fix a leak
Clearing a blockage can stop an overflow, but it will not repair cracked fittings, failed seals or a damaged downpipe. Those need a separate repair.
Not sure about your own property?
If you are in Ryedale or nearby, send Will a couple of photos and a short description. He can usually tell you whether the surface needs a closer look before quoting.