Whenever it rains, a huge amount of water is dumped on your roof. All that water should run off without any problem, but if it all just went straight down, it would make quite a mess. To control where the water comes down, most homes are equipped with gutters and downspouts. If your roof doesn’t drain properly, it could take damage, and if your gutters and downspouts get clogged, the water could back up underneath the roofing and do damage. To prevent this you should keep your roof clean, clearing away leaves and branches that might end up in the gutter.
It is also possible that your gutters start sagging down from old age. This could be a danger, since they could become so loose over time that they could fall down and hurt someone. On top of that, it will no longer work up to capacity, so you should either repair them or replace them.