Gutters are in no way a requirement for your home. They are used to channel water from your roof, sometimes away from flower beds that have small plants, from walk ways, driveways, or patios. Sometimes downspouts from the gutters are used for channeling water toward trenches in yards that channel water as well.
We install 5, 6, & 7" gutters. Have Dennis come out and measure the length of aluminum gutters needed. He will come out and give you the cost of the job and the colors to choose from.