Wikipedia:Not everything needs a navbox
 | This is an essay. It contains the advice or opinions of one or more Wikipedia contributors. This page is not an encyclopedia article, nor is it one of Wikipedia's policies or guidelines, as it has not been thoroughly vetted by the community. Some essays represent widespread norms; others only represent minority viewpoints. |
 | This page in a nutshell: Navbox templates can be useful as a tool for navigation, but use them sparingly. |
Navigation templates (also called navboxes) are useful tools, as they provide an easy access point for a large clump of several articles. In moderation, they are a good thing.
Some people seem to believe that there should be a navbox on every page, but not everything truly needs a navbox. Even the most clueless new user can find their way from the first article to the next in line if there are only two, three or even four. For instance, a film series with only two or three entries could easily have a "sequel" header on the first film's article, with a {{For|sequels|Foobar|Bar|Baz|Quux}} pointing to the articles on the sequel(s). Perhaps the most insulting is a navbox with only two entries: it's just an extraneous little piece of coding that offers yet another, redundant gateway to the next article. Such a navbox practically screams, "hey, you need yet more help getting from Point A to Point B, don't you?"
Almost as bad is when a new user creates an article on a band and creates a new template about the band in the process. Most often, this template will include a link to one album, one single, and list all the band members when none of them is individually notable enough for a standalone article. No doubt, most templates of this ilk are created in good faith: after all, the new user is most likely following the example set by the article of a much more notable band which does warrant a navbox. Some would even argue that there is potential to expand since the band is new and will release multiple singles that warrant a template, but there is no reason to keep such a template around and sit on your hands until it's necessary. In the meantime, all it does is clutter up the article. Why not hold off for a while? It's not like there's some deadline you have to meet.
Worst of all, with too many navboxes piled up, template creep can start to set in. And before you know it, the article is suddenly more template than article.
A good, but not set-in-stone rule to follow is the "rule of five": are there presently at least five articles (not counting the primary article) on which your navbox will be used? (For instance, five books or films in a series; five singles or albums for a music article; five products by a common company; five members of a common group such as a band, comedy troupe, etc.) If not, then you probably don't need a navbox just yet. As with all policy and style suggestions, common sense and consensus should prevail.
The editing guideline WP:CLNT (about synergy between Categories, Lists, and Navigation Templates) gives guidance about when navigation templates are useful (e.g. when there is "a small, well-defined group of articles") and when they are not ("templates with a large numbers of links are not forbidden, but can appear overly busy and be hard to read and use"). One indicator of usefulness is if an editor would otherwise be inclined to link many of these articles in the "See also" sections of the articles.
Finally, keep overlap in mind. For instance, if a director has only ever worked for one studio, then it doesn't make sense to have a "films directed by" navbox for the director if all the films are also in the studio's navbox.