Combing
Sweaters are favored by many because of the comfort and warmth they offer, but not as many consider the regular care required to maintain them.
As a garment knit from yarn, their special construction allows them to have a lot of give and surface texture, which lends to their cozy feel. However, this construction leaves them prone to pilling, a reaction of the fibers to lift and separate and turn into those little balls that look less than appealing. Nearly all sweaters pill, especially in high friction areas, such as under the arm, so it is up to us to manage them through the practice of combing.
There are a few tools out there up to the task, including special stones and a plain old straight razor, but I prefer a proper comb, such as the cedar comb made by The Laundress, which has a gritty mesh screen on the side of the tool.
It requires a little practice to apply the right kind of pressure with your stroke, but once you get the hang of it the pills are easily removed, and, if working with a natural fiber like wool or cashmere, the natural oils are coaxed out of the fibers and help to condition the garment.