Wikivoyage:When to use dates
No travel guide can ever be completely up to date. Prices increase regularly, borders close and reopen, airlines commence and discontinue routes.
Our wiki format allows us to respond to these kinds of events promptly. In theory, this means that our information can be kept current by updating it regularly as events happen, while maintaining a clean and concise guide. The reality is that it can take a while for some destinations to be revisited and for the information to be updated in the guide. Meanwhile, knowing whether information is current or dated can be very useful to travelers using the guide.
We need to find a balance between adding a date to all facts and maintaining an uncluttered travel guide. This is a guideline to help achieve that balance.
Dates on prices 
Prices for attractions change regularly. The general rule is that we don't append a date to a price. When a price changes, we update the guide without retaining any previous pricing information.
Exceptions may apply in circumstances where prices may change rapidly. For example, in cases of rapid currency devaluation it may be relevant to note whether a price is prior to or subsequent to the movement.
Dates on cultural events 
For festivals and other cultural events try, if possible, to specify the date in such a way that is valid for any year.
- If the event falls on the same date every year, then list the date without a year. Albanian Independence Day celebrations are held 28 Nov every year
- If the event is held relative to another date or event, specify that. The Melbourne Cup is held on the first Tuesday in November or The celebration of the ringing of the bells is held the first Sunday after Easter.
- If the event is held on a different date every year, then list the precise dates including the year. If the event is always held at a particular time of year, then you may want to list that too. The tulip festival is held in early spring, (12 Mar 2010).
Opening times 
Dates and times are used to indicate scheduled opening times. When an attraction or establishment is only open on certain dates (seasonally or otherwise) these dates should be included in the guide.
Permanent closure or cessation of service 
The general rule is, once an establishment has closed the listing should be removed. Don't just append the information that it has closed. When popular or iconic establishments, which are documented extensively in other travel guides or on the web, have closed it may be appropriate to mention this in the guide.
Similarly when flights, bus routes, and other services are discontinued, the information should usually be removed. An exception exists when the route was popular, documented elsewhere, or remote. For example we probably don't list bus route changes in a major city, just update it to reflect the current situation. However, if the ferry Lonely Planet says services a small Indonesian island no longer runs when you attempt to catch it, then that is worth listing with the date on which that occurred.
Our goal is to give only current information to the traveller, including old information only when it is useful to avoid being misled by information commonly available elsewhere.
Transient information 
If a piece of information is somehow temporary, then a date should be added. For example, if a road is closed by construction then you should add the date you know it was closed. If possible add any information you have about the reopening.