Tardis:Even good categories can be removed

The natural extension of our guideline to not over-categorise is that sometimes categories you think of as being perfectly sound will be removed from a page. Here are couple of the broader points about category removal. But these are just a couple. Other reasons certainly do exist.

Technical reasons
The big thing to understand about categories is that they are essentially organisational tools, not genuine content. If you're trying to add to the content of the wiki by adding categories, you should probably rethink your editing strategy. You should prioritise editing the article proper over adding categories.

Categories are used by several products here at FANDOM, and it's possible that by over categorising, you're inadvertently having a negative effect upon the editorial content of the wiki. A recent example happened in the Doctor Who App. Because there were a few comic stories that put the Master in a companion-like role alongside the War Doctor, the Master was put into Companions by Doctor. The Doctor Who App selects images to represent categories based upon the popularity of the pages in the category. Well, the Master is one of our most popular pages, so its infobox image was chosen as the "representative" face of a companion!

This same thing happens in the mobile web version of Tardis. If you were to navigate to the companions categories on your phone while the Master was in those categories, the young Master from The Sound of Drums would greet you.

Worse, because we use a carousel image for the Master's infobox -- and mobile versions of the site can't represent that -- what gets picked is the first image in that stack of slides. And there's no story that's ever suggested that the very youngest Master was a companion of the Doctor.

Editorially, that is -- of course -- unacceptable. For the sake of noting one very minor part of the Master's life, we're telling a visual untruth to the majority of our readers. (Yes, the majority of Tardis readers are on mobile.) So the solution is to take the Master out of companions categories. And then, any stories which have the Master as a potential "companion" should be explained fully in the body of the article.

Equally, the new, 2017 page header brings with it categories above the title. It's important that these categories be truly representative of the page as well.

The obvious, the trivial and the marginal
Leaving mobile concerns to one side, though, it's important to remember that categories should genuinely be meaningful.
 * Categories that tell us things that are self-evident may be subject to removal, or at least some of their members might be de-categorised. Time Lords who have been inside the Doctor's TARDIS shouldn't really include the Doctor himself. Of course he's been in his own TARDIS. For a similar reason, there's no need to put every individual Zygon or Alpha Centauran in Non-cisgender individuals, or every Time Lord in the Virgin New Adventures in Non-heterosexual individuals just because those stories describe the whole species a asexual.
 * Sometimes, the information in a category may be super trivial. For instance, individuals who wear necklaces isn't all that meaningful -- and is even potentially vague.
 * Some possible categories would have too narrow a definition to be useful. For instance, sufficiently many characters describe themselves as "gay" or "lesbian" to have a Lesbian individuals category — but we wouldn't be allowed to put Bill Potts in either, because no valid source has her identify as such. That would be ridiculously confusing, so we just have Non-heterosexual individuals.
 * As T:OVER-CAT explains in greater detail, you shouldn't put every possible category on a page, particularly when talking about people. Instead, you should choose the ones that most specifically apply. If Sarah Jane were to pick up a guitar in one episode and strum a few malformed notes, that doesn't mean she should be in Musicians.