Echo contents of stylesheet

  1. The speed difference is very small and you would need a very busy site to notice it.

  2. Do not use require_once - _once makes no sense in this case, it doesn’t really hurt but adds a microscopic overhead.

  3. The biggest speed difference will be if you use an opcode cache (opcache) on your server (which is always a good idea!). require and include will be picked and compiled by the cache so in practice the external file will not really be loaded after the php code has been cached in memory. file_get_contents, on the other hand, will have to be executed every time.

  4. I would still prefer linking in html like @Gandalf suggested.