Wikipedia:No cite-by date

Maintenance tags like. When a statement in an article requires citation, the length of time for which it has been uncited is not a criterion for the statement's removal.

With that said, the presence of long-uncited statements often linked to other problems that do merit a summary deletion, such as the statement being original research, or its being undue within a given article. Clarity of purpose and communication thereof is preferable to simply noting the age of an uncited statement.