The MoS suggests that the first instance of any given acronym in the body of an article should be expanded, and optionally repeated in the lede. Other instances of that term should use the acronym.
In large articles, finding and editing such terms is a serious problem. A JS tool, like the duplicate links checker, would make this task much easier. Orders of magnitude easier!
Example: in a recent article I used the term "printed circuit board (PCB)" and then had many instances of "PCB" after that. However, after moving some content around, the definition ended up below the first instance of "PCB". This tool would help avoid (and fix?) these sorts of problems.