Key:building:age

This feature has been labeled as deprecated. The recommended replacement is: start_date=*.
The reason is documented in Deprecated features. You are still free to continue to use or interpret this tag as you see fit since OpenStreetMap does not have “banned features”.
Under no circumstances should you (semi-)automatically change “deprecated” tags to something else in the database on a large scale without conforming to the automated edits code of conduct. Any such change will be reverted.

The building:age=* key was used to describe the approximate age of a building=* or the period of construction. This tag has mainly been used for a few imports.

This tag is problematic because it is immediately outdated the moment it is entered into OSM, forcing the data consumer to retrieve the way's history to reconstruct the current age. The more common way to tag the age of a building is by using start_date=* to specify the approximate date or year the building opened or construction of the building finished.

Common used values of building:age=* were:

• post_2000
• pre_2000
• 10_to_30
• less_than_10
• more_than_30
• 10_to_20

See also

• start_date=* - much more common tag, recommend to use instead

building:age=*

More details at taginfo

• building:age=*

If you know places with this tag, verify if it could be tagged with another tag.
Automated edits are strongly discouraged unless you really know what you are doing!