Mend your knits
When you have a small hole in your knit, the first thing you need to do is buy wool yarn, in the same color as your knit or sweater, from your local sewing or fabric store. Turn your sweater inside out, and by bringing a loop on one side of your hole, together with a loop on the other side, you start bringing the hole back together. Work uproar way slowly to the end of the hole, and close it up by making a small knot, or simply by pulling your yarn tightly through the last loop 2-3 times.
Picture source: tashamillergriffith.com