Content Expiration - IIS 6

Question

If I set the content expiration for static files to something like 14 days and I decide to update some files later on, will IIS know to serve the updated files or will the client have to wait until the expiration date?

Or is it the other way around where the browser requests a new file if the modified date is different?

Sometimes I update a file on the server and I have to do a hard refresh (CTRL+F5) to see the difference. Currently I have it to expire after 1 day.

Answer 1

You want ETags

Answer 2

The web browser, and any intermediate proxies, are allowed to cache the page until its expiration date. This means that IIS might not even be aware of the client viewing the page.