Having never lived in an area with significant water-from-the-sky challenges I had never really thought about rain gutters. I thought I knew what they were for: To keep the rain off of your head while you are entering or exiting the house. And, yes, they help with that.
I happened to look at a book on houses and water management recently. It turns out that rain gutters also serve a more important role.
In areas that have heavy rains the gutters are necessary both to protect your basement from flooding and to direct water away from your foundation. These rain gutters should direct water well away from the house.
In comparison, our rain gutters are much more optional. As far as our foundations are concerned, concentrating water into one spot and letting it drain directly next to the house, as many of ours do, is potentially worse than not having rain gutters at all.
