A quality soft wool pillow can last you many years, a lifetime if you take proper care of it. You'll want to keep it protected from dirt and dust by using a pillow protector and pillowcase made from natural fibres like cotton or linen.
Once every few months, you should also put your wool pillow in the sun for a few hours to sanitise it. With proper care, your wool pillow will continue to be a comfortable and supportive part of your nightly sleep routine for years to come.