Tardis:Even good categories can be removed

From Tardis Wiki, the free Doctor Who reference
Even if it's true and well-named, a category still might be removed by admin.

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

Categories 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.

The obvious, the trivial and the marginal

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 as 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.
  • Finally, 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.