They enable you to simplify sentences where the same general idea is expressed two or more times.
- On their wedding day Jhon gave Mary a gold ring and Mary gave Jhon a gold ring.
* Using the reciprocal pronoun, "each other", this could be rewritten:
=> On their wedding day Mary and Jhon gave each other gold rings.
- Peter and Mary kissed each other.
* In this example "each other" indicates that both people involved in the action of "kissing" got the result, kisses, at the same time.
If you need to refer to more than two people, say the students in a classroom, then we could use the reciprocal pronoun, "one another".
- The students in this classroom cooperate with one another.
- The teachers gathered to congratulate one another on the year's conclusion.