Any fabric can bobble or pill—aka form patches of fuzz balls—as the fibres stretch and break as a result of friction. Clothes rub against themselves while you’re wearing them, and against other fabrics during the washing and drying procedure. The areas worst-hit by pilling are the parts of clothing that receive the most abrasion in day-to-day wear, such as the underarm area and the side of jumpers and cardigans.
It is perfectly normal for the fibres to be pulled out of your clothes in the above processes, and there is little you can do to stop bobbling completely. However, that doesn’t mean that you shouldn’t take a few cautionary measures to prevent your clothes from bobbling in the wash.
The most bobble-prone fabrics are wool, cotton, polyester and nylon, while linen and silk are generally safe from the formation of fuzz balls. Synthetic fabrics—especially blends mixing multiple types of fibres—are more likely to result in bobbling than are pure, natural fabrics, like wool and cotton. Also, the looser the weave, the more prone the fabric will be to bobbling, which is why you hear about "jumper bobbling" instead of "jeans bobbling."
Most importantly, different types of fabric require different washing methods. To see how you should care for your piece of clothing, check the garment’s washing label.
