We recently added a "Last started at" column to the Chains tab within Chain Builder. This column shows the last time that each chain was run and can be used to identify inactive or outdated chains that haven't been used recently.
This feature is not retroactive, however, meaning chain runs prior to its implementation won't be detected. For this reason, any chain that hasn't executed since February 26, 2024 will display a "Last started at" status on the Chains screen.