Forum Moderators: not2easy
I don't use them at all. I try to have a very few CSS files that I <link>. I try to have one that covers most of the site, and might have a few to do some special things or to have a heavy part of the site not bother all the other pages.
For e.g. print styling I use in side the CSS file itself
@media print {
#menu, #crum, #ads {display:none;}
}