Response.Expires

The Response.Expires property specifies a length of time in minutes a page should be kept in the cache and how long the page is cached browser it expires.

The first line of code causes the page to be refreshed (reloaded) every time it is accessed, rather than being stored in a cache.

In the second example, if the user returns to this page before the 15 minutes are up, the cached version of the page will be displayed.
<% Response.Expires = -1%> :Should not cahhe the page

<% Response.Expires = 0 %> :Refreshed (reloaded) every time it is accessed

<% Response.Expires = 15 %> Expire after 15 minutes

<% Response.Expires = 1440 %> Expire after 1440 minutes (24 hours):