Should I disable ETags on my page?

Some sites (including the otherwise-wonderful recommend disabling ETags on Web pages to improve performance, using something like this in a .htaccess file:

Header unset ETag
FileETag None

However, that advice is geared towards sites that serve a single static URL from multiple copies of underlying files (for example, from a cluster of servers that use separate disks).

We don’t do that, so turning off ETags doesn’t help performance on sites we host. Leaving them turned on usually improves performance a small amount.

The only situation we’re aware of where disabling ETags is useful is if you want to avoid an obscure bug in the Apache Web server software that sends the same ETag value for compressed and uncompressed representations of a page, although in practice it doesn’t appear that the bug causes any actual problems.