Everything on the outside of a house is being worked on constantly by weather, and none of it announces when it needs attention. A blocked gutter costs nothing to clear and a great deal to ignore, because the damage it causes appears somewhere else entirely, usually inside, usually months later.
That delay is the whole problem. By the time a stain shows on an upstairs ceiling the cause has been running for a season or more, and the repair is no longer the gutter. These guides deal with the outside jobs on the basis that catching them early is the entire saving.
Each one covers what to look for, when in the year to look, and the point at which a job stops being yours and wants a tradesman with a ladder, a scaffold or a licence.