Obsessing about server headers

and cacheability

[millie]

I have been checking around to see what other big sites are doing and it seems that many are "stale". Mine too! eg:

[example.com...]
Expires -
Cache-Control private
Last-Modified -
ETag -
Set-Cookie aspsessionidqsdqarcq=MBJCGDKCLPCLJKAFLBGCLGKN; path=/
Content-Length 12.3K (12635)
Server Microsoft-IIS/5.0

This object will be considered stale, because it doesn't have any freshness information assigned. It doesn't have a validator present. It won't be cached by proxies, because it has a Cache-Control: private header. This object requests that a Cookie be set; this makes it and other pages affected automatically stale; clients must check them upon every request.

#

I've read the tutorials etc but:

1) My pages aren't going to expire so it would be incorrect to say they would expire after 24 hours or whatever. Kind of like playing a trick on the useragent?

2) Last modified - it's database driven so if I use IMS it has to be the current date and time to prevent problems regarding the content that is served. I'm not comfortable with this because it seems like another trick. The content was not updated "now" so if the useragent makes a request and the identical content is served even though it is claimed that the content has changed this must be bad.

3) Set cookie - I want to track referrer info so is there a work around for this?

4) So few sites seem to bother with cacheability that I'm wondering how important it is.