I almost always work my Watchlist by oldest edit date.
I have link variations on my Scratch Pad that take me to different page sorts (privacy, birth date), so there's never a dull moment for me!
Often I work by surnames, or at least by family groups. The Ancestors/Descendant links on profiles are very useful when working on family groups.
My base list for oldest edit is at August of 2018, but occasionally I discover an older profile that has slipped through the cracks.
In my opinion, working from oldest edit provides the most benefit to the tree. As you say, we are constantly improving functionality. In addition, we have had guideline changes that we should try to integrate, especially into profiles that haven't been touched in years.
All for the greater good!