I'm using a cms (Wordpress) and have a gaggle of external stylesheets I'm loading on each page, though some of these stylesheets are page specific. Overall I'm getting bad scores from Yslow and Page Speed so I'm considering adding some php conditionals to tell the browser to load only the page specific css files as necessary. However, I'm wondering if I'm actually going to decrease load time since I'll be adding more PHP requests to for the browser.
By adding some php conditionals you are not adding more PHP requests to for the browser.
Honestly, PHP do not make requests to the browser at all.
And adding some conditionals to the PHP code will affect no performance. But save browser from unnecessary CSS requests.
So, it would be better of course.