Considering the number of times: there's no technical limit on the number of edits you can make. Some posts have lots, which might alter your bar for "a fairly large edit history". Posts used to be automatically converted to community wiki after enough edits, but that no longer happens ever. The only real limit is that at revision #50, it might be healthier to let that post go in its imperfect state and turn your attention elsewhere.
So if you want to improve your post, go ahead, if you consider it a worthwhile improvement. That can include single word changes (I have done that) or big rewrites to communicate the same message better (see revision #4). Rewrites for entertainment value is fine too, just make sure it's good, and aids communication, or at the very least, doesn't diminish it.
If you're trying to benignly rewrite your question, you may want to carefully avoid breaking existing answers with your changes - i.e. bringing your question to a state where they're not quite valid answers to it any longer. That can be bad. If that's a disconnect because you changed how you're asking your question, that might impair readability for visitors to the site. However, if you really did preserve the meaning of your question, it might simply be exposting an answer that wasn't solving your problem very effectively in the first place.