It has been suggested that if some of the pages on my site change for mobile users, but some don't, google will not like me having a " Vary HTTP header"
does anyone know if search engines will not like having a Vary HTTP Header on pages that don't have a mobile version? - It seems that it's possible to implement on a page level, but after reading the comments I'm still unsure if there is any real problem around doing it as a global command. Sorry if I missed something in the comments. I'm just trying to understand a statement in the original comment better.