Hair frays at the ends. It becomes fragile and prone to tangling. Hair actually grows longer with occasional trimming -- it prevents the split ends from propagating.
You don't necessarily have to go to a salon for that, especially if you have straight hair. Just comb it flat and have a friend cut a straight line. You can even do it yourself, if your hair is long enough, though it will be a bit ragged.
You can also get it cut for a lot of other reasons. Hair can be shaped and layered, for a style that suits your current preferences. Curly hair in particular can simply look bushy if it's not given some kind of shape.
You don't have to care about your appearance, but if you really don't ever get your hair cut, then you're lucky that you have the kind of hair that doesn't turn into a felted ball.
You don't necessarily have to go to a salon for that, especially if you have straight hair. Just comb it flat and have a friend cut a straight line. You can even do it yourself, if your hair is long enough, though it will be a bit ragged.
You can also get it cut for a lot of other reasons. Hair can be shaped and layered, for a style that suits your current preferences. Curly hair in particular can simply look bushy if it's not given some kind of shape.
You don't have to care about your appearance, but if you really don't ever get your hair cut, then you're lucky that you have the kind of hair that doesn't turn into a felted ball.