While improving posts is a laudable goal, editing others work is a big responsibility. To the extent that the editor changes the submitters' work, the editor is assuming a degree of ownership of it. And if the editor gets it wrong (and editors are human) the editor doubly harms the community by degrading an answer and potentially offending an author - who might never return.
To encourage members at any level of points to edit posts with non-trivial changes "any time you feel you can make the post better", and not to say a word about the need for restraint, seems like a recipe for trouble. I think that a rewrite of this overly-liberal policy is needed in order to balance the privilege with the responsibility.
It also seems that for this community, 1000 Reputation points might be a bit low for this particular privilege. Is there a way to retrieve all non-poster edits in order to review them? Some numbers would help establish whether there is an existing problem and its magnitude.
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 Try to make the post substantively better when you edit, not just change a single character. Tiny, trivial edits are discouraged.