In reference to ASP.NET Caching, what is the purpose or reason for sliding expiration?

Question

I am looking for a good explanation of why one would use sliding expiration when caching data in a Web application. It seems as if you would always want to cache content using absolute expiration so the data is forced to be refreshed. With sliding expiration you risk having your data be cached indefinitely. Is it only useful for caching static data? What is a common scenerio for when sliding expiration is helpful? Thanks.

Answer 1

Some things might be okay to be cached indefinitely, but only if you have enough memory to keep them.