It would be useful to have a written guideline to address tasks assigned to someone for years without any reported activity, usually with a priority that doesn't reflect the reality either, like "Normal".
Someone like @Aklapper, whose job is to keep Wikimedia Phabricator in good shape, does remove assigned users from tasks and does reset the priority accordingly. However, for occasional triagers having such guideline would be useful, to be certain about when such action is appropriate and avoid potential discussions.