Can someone tell me in what cases is necessary or useful caching an ajax call (cache: true) ? or when not? Could you give a practical example?

Can someone tell me in what cases is necessary or useful caching an ajax call (cache: true) ? or when not? Could you give a practical example?

Can someone tell me in what cases is necessary or useful caching an ajax call ( cache: true ) ? or when not? Could you give a practical example?