What is Caching and Why Use Caching?
Caching is the process of storing results of a complex (or not so complex) computation in a cache or temporary storage location in order that they will be accessed directly without re-compute everything.
There are two main reasons for using caching:
1) The application becomes faster for the user. A faster website results in happier users, which ends up during a better conversion rate.
2) You need less hardware for the online server because you need less CPU and RAM resources for processing the queries.