This weekend, I’ve dedicated to resurrecting a few more plugins which were withering away without updates between 5-7 years!
They all needed surprisingly little to get back up and working again. Disable User Gravatar and Cursor Trail actually worked out the box but spat out a few PHP errors.
In all cases some reorganization of code, updating it to use some ‘best’ practices will have improved functionality and performance. Mostly, they got a clean up, and maintaining them should certainly be a lot less (if any) time-consuming.