I was just looking at our site on WebPageTest.org and one of their recommendations for speeding up a website is:
ETag headers should generally not be used unless you have an explicit reason to need them
I was wondering what this means. Does it mean that static content you know will not be changing should not have them, or does it mean content you know will be changing regularly shouldn't have them, or does it mean that you shouldn't use them generally unless you have a specific need.
If it's the latter, when is the right time to use them? Thanks for any help.