The primary, over-arching rule is:

* Protect the page to prevent vandalism or stop an edit war.

(If that's not rule #1, it should be.)

It doesn't matter if I've edited before or not. Someone who wants "their" version will always complain, anyway.

Another good rule is:

* After protecting a page, don't make any changes that make other contributors feel you are taking advantage of your sysop rights.

I've made many edits to protected pages (like [[Silesia]]) which (technically) violate some rule, I suppose. But I always ask people in the Edit Summary or the Talk Page if they mind or not. And if someone minds, I generally offer to undo my edit (just to be fair).

Uncle Ed