Cage allows you to get approvals on the record! Every file can have multiple approvers and each approval is time-stamped with the date and time so you know exactly when it happened and by who. Have a few clients who need to approve the work and need a nudge? You can send an approval request and Cage will automatically send a nice reminder email to them with a link directly to the file for you. Files that have been approved are denoted with a red heart and the number on the thumbnail too.
Approvals show up in the activity feeds for the project and the account too, so in addition to the email notifications you get for approvals, you'll always know if someone has approved the file.