Quality gutters should last at least 20 years, especially if they are made from galvanised steel or aluminium. Copper gutters however, and last up to 50 years if kept clear of standing water and erosive debris.
If there are no gutters fitted to your home, when it rains, the water flows directly off the roof and onto, and then down, the walls. This can cause major erosion of soil at the foundation of the house. Erosion then causes water to pool against the base more and more, leading to structural damage.