Wikipedia:As of

The "as of" technique is a method to deal with information that will date quickly. Some articles have information that is valid only at a specific moment in history, such as population statistics and current events. If you suspect that a fact in an article will become dated at some point in the future, and want to ensure that people will update it, include a tag of the form

with the year of validity in place of year and the month number in place of month. See the {{}} template for additional options and detailed examples.

Every individual, non-contiguous statement in an article that may date quickly should be so tagged, even if there are several such statements that link to the same year. Otherwise, it is possible that when one statement is updated, other statements in the article might be overlooked, and no one will realize that they need to be checked also.

Usually "as of" is used only in cases where an article is intended to provide the most current information available, and will need updating in the future. It should not be used for historical information that will not change. For example, a mention that the historical "population of Toledo, Ohio, was 13,768 as of the 1860 Census" should not be tagged, as it is a historical fact which will not change. It is appropriate to tag "the population of Toledo as of the 2010 Census was 287,208" (where the 2010 Census is the most recent available at the time of writing). The date used for a given statement should be the current date (for currently valid statements), or the date on which the data were obtained (for example, when using Census figures).

"As of" should not be used with future dates, as it will cause the article to be placed in nonexistent categories. Instead, use {{}} to mark when the next event will occur. Here are two ways to correctly mark statements with future dates:

     {{As of|2017|post=,}} construction is expected to finish in 2027 and cost US$28 billion.

     Construction is expected to finish in 2027 and cost US$28 billion.{{update after|2027}}

Remember to always use precise language when writing about future or current events. The statement should make sense to a reader years into the future, even if the information has changed. If it is possible to predict when a statement will need updating you should also use the {{}} template to indicate when a statement will become out of date. In the above statement the most obvious date is 31 December 2017, after which time construction will have finished or the statement will have become inaccurate. In either case the article should be updated to reflect this.

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