Currently, all of the pages on my website are made static by requesting the dynamic page, writing the resulting HTML to a file on disk (eg index.html.static) and then showing that to the user, if it exists, when they request, for example, index.html.

This works just dandy as long as the content of the page doesn't change. If the content changes the page shown is then out-of-date.

I'm now thinking of adding a bit of dynamic content to the pages, which would mean that this type of caching stops being feasible for the entire site (the dynamic content that I'll add will go in a common sidebar).

So my question is: Which is more important - the caching or the dynamicness of the pages?

The site doesn't get a lot of visitors and caching headers are still added to the pages so speed isn't really a problem at the moment.