So here's what the Editing Help says:
When should I edit posts?
Any time you feel you can make the post better, and are inclined to do so. Editing is encouraged!
Some common reasons to edit are:
- to fix grammatical or spelling mistakes
- to clarify the meaning of a post without changing it
- to correct minor mistakes or add addendums / updates as the post ages
- to add related resources or hyperlinks
Tiny, trivial edits are discouraged - try to make the post significantly better when you edit, correcting all problems that you observe.
But having just had an edit rejected as "makes no sense as an edit" (which I then put in a comment, which was then deleted), I suspect that the standard is actually not "any time you feel you can make the post better."
The last line especially confuses me; I would consider most spelling/grammatical fixes to be trivial unless you're missing a "not" or half a sentence. So I think this may have set me into thinkiing that edits should be more substantial than is normally accepted here.
So my question is: How do I know when to edit someone's question or answer vs. commenting and suggesting they do so?