Question About Editing Blog Posts. Chime In, Please!

So lately, my posts are becoming longer. With this added length, there is more content for me to review and subsequently edit for clarity, added information, or humorous quips. I first published the article right before this around 10pm last night. Here I am now, 20 hours later, still changing things around in it. Some of these changes add content to the post, others are just small edits, mostly for clarity. I worry that readers don't get to see these changes.

Basically, my question to you, if you publish content online, is how do you deal with edits? Do you just do everything in a word processor first, make sure it's "right," publish it, and then forget about it? If you do edit it after publishing, would you say that it's a bad idea to make significant changes? Does my RSS feed update and notice that the content is different, and re-display the post as a new and unread item? This last question is something I have wondered about; sometimes my RSS reader picks up posts again as new and I can't really figure out why. I think other readers I've used in the past have done this too. If this is the case, I've never paid any attention to possible changes in the posts that re-appeared.

Is there a good way to deal with this? I wonder if maybe someday someone will create a RSS reader that's smart enough to see changes made in individual posts, and highlight the stuff that's different.