A pool client requests a resource from the pool and performs desired operations on the returned resource.
When the client finishes its use of the resource, it is returned to the pool rather than released and lost.
Pooling is also useful when the latency is a concern, because a pool offers predictable times required to obtain resources since they have already been acquired.
These benefits are mostly true for system resources that require a system call, or remote resources that require a network communication, such as database connections, socket connections, threads, and memory allocation.
Pooling is also useful for expensive-to-compute data, notably large graphic objects like fonts or bitmaps, acting essentially as a data cache or a memoization technique.