When are letters considered necessary for communication?

Letters are considered necessary for communication primarily when a permanent record is needed. This is because letters provide a tangible, formal document that captures the details of the communication in a way that can be archived and referred back to in the future. The written format of a letter ensures that the specifics of the conversation, such as terms, agreements, or important discussions, are preserved.

In situations where a formal record is essential, such as legal matters, business agreements, or important notifications, a letter serves to provide evidence of what was communicated, the date of communication, and any decisions made. This permanence and formality distinguish letters from other forms of communication, which may be less reliable for maintaining a record. Other options may focus on more immediate or informal communication needs but do not fulfill the requirement for a documented and verifiable exchange.