If modified since / last modified headers

How much different should the content be?

[graywolf]

In response to this thread

[webmasterworld.com...]

I have added last_modified date to all of my pages. My question is how different should the content be for me to consider updating the date. For example say we have a tab navigation banner like Amazon, and we add or delete a tab, but the rest of the page stays the same. If the navigation banner is consistant across the entire site would this be enough to change the date for every page? If not how much change would be?

[lazerzubb]

Isn't it done automatically, each time you change anything on any page, a new date will appear when you request Last Modified or?
(ps, i have never owned an server, not in my house/apartment anyway)

[Check6]

That thread is about the "If-Modified-Since" header the web server responds to which is not the same as "last_modified". Have you hard coded a meta tag with a date in each page?

You don't need to do anything to your pages to use "If-Modified-Since", you just need to make sure that what ever web server your on supports it. When the page request is sent to the server it includes the date the robot last saw the page, the server checks the date and if the page has been modified since sends the page, if not it sends a 304 (Not Modified) response.

[graywolf]

I have the dates in a database table. Static pages I publish with the date/304, dynamic pages get a no chache message.