User blog comment:Rappy 4187/Technical Update: April 20, 2015/@comment-1192804-20150421130738/@comment-452-20150424173313

"and !important should be avoided unless absolutely necessary."

I respectfully disagree, I already used !important in my background style, and this recent update didn't break mine, so I feel that my use of !important was worth it.

I'm aware of the meme of "Don't use !important unless you have to", but that's more to do with CSS you write yourself, and I think it's perfectly fine to use them when overriding on Wikia, because there's no reason for Wikia admins to just through hoops after every class change just for the sake of adhering to that repeated meme.

It should certainly be used in moderation, and is certainly not needed in most cases.

Here's a writeup about when using important is the right choice, which includes the quote: "To make your [...] class super robust and not easily trifled with, put !important rules on the values.", which certainly applies to the case of background override classes on Wikia.