Drum heads (also commonly known as drum skins) are essential to ensuring that you are getting the best sound out of your drums or drum set. These drum heads necessarily take a beating, and to consistently create the best sound, you should regularly change your drum heads. Even if you don’t play your drum or drums that often, it is still beneficial to do this.
Drum heads stretch over the vessel to create the drum as we recognize it. In essence, they are the surface you strike when you play the drums. As you strike the drum head repeatedly, it loses tightness and the tension and sound changes. When the head is tight, though, the sound is more uniform and clean. This is why they need to be replaced often. It is also more difficult to play something like a roll on a drum head that has dents.
Try to change your drum heads at least every six months, maybe more often if you play regularly. It can be easy to forget as you get used to playing a worn-down drum head, but the difference is noticeable every time you replace the drum head and have a new surface on which to play.