Wikipedia:Avoid data-hoarding

This essay describes issues about collecting extensive piles of information about a subject, analogous to hoarders cluttering a room with stacks and stacks of items, filling the room to the ceiling. Likewise, editors must be careful not to crowd, or over-stack, an article with too much data, to the point where all the minute details clutter the page and obscure the overall view of the topic.

The solution to an obstructed room, filled by hoarding, is not only to store many items in separate storage areas, but also to throw items away, or delete excessive items. Similarly, some sections of a cluttered page could be moved into spinoff sub-articles, but often, a large amount of detail should be deleted, when it does not help to explain the reasoning, or description of events in the article.

Examples
For example, in a crime article about a theft from an art gallery, there is no need to itemize every painting or item missing, with size, color and provenance background, even if posted on a crime-events website which repeated details from police reports or an art-gallery press release. Instead, the information should be summarized, by type, counts, artists, and value (etc.), except for specific items noted in many sources, or where details would explain related events, such as how the items were taken or how the items were tracked or recovered. In general, facts within an article should cross-connect to notable aspects of the topic, rather than be presented as a "laundry list" of items with little specific impact on the overall topic. For example, in an art theft, an obscure item should be mentioned only if it was crucial to the crime's discovery, tracking, or perhaps capture of some thieves.

In sports articles, there has been the problem of recounting the career stats of an athlete's or team's entire history of numerous wins and losses. Those details could be reduced to being a summary of counts, or specifically noting a list as showing only the "top 20 wins" or a similar cap on the total myriad of details about the topic. The focus should consider the level of detail appropriate for an encyclopedia, versus contents of a "record book" about those sports.

One somewhat common occurrence happens when biographical articles for especially academics have large sections that list every publication and media appearance that one might include on a curriculum vita. This unsatisfactory practice does not help the reader understand which publications or appearances are the most important. Instead, include lists of selected publications or noteworthy appearances preferably using third-party reliable sources to identify them.

Data hoarding in navboxes
An especially difficult problem can occur when navboxes are expanded, with excessive clutter. Navboxes often act as the boxified contents of a category, tacked onto the end of an article. Although many navboxes list similar articles, at a similar level of notability, some other navboxes become cluttered with links to pages which are much different in scope, or notability, and are only remote tangents to the topic of the original article where the navbox has been inserted. Once navboxes link remote tangent topics, then the focus can become a "slippery slope" where even navboxes with rare tangents are linked. For example, when creating navboxes which link every other competitor of an event, then some articles have contained dozens of navboxes, one for each major tournament or competition which a person has entered.

There are emerging standards to limit the use of navboxes, and infoboxes, to reduce the clutter in an article, or avoid over-simplification of a topic. For example, with film actors, the related navboxes have been pruned to remove filmography lists, so only an entire filmography sub-article should be linked in a navbox, rather than linking all the major films of an actor. It is preferable to list an actor's films in a sortable table, which could be sorted by date, genre, or box-office ticket sales, etc. Listing films in a navbox can over-simplify the ordering and give "top billing" to films by alphabetic order, rather than ranking by date or box office, which might be a more important factor for the reader.

In general try to limit the number and size of navboxes, in proportion to the size of the articles. A small article should typically have only one navbox, or none at all. Otherwise, the navbox becomes undue weight in the article, as getting more coverage than the main topic of the article.