POLL: When is it ok to edit a blog post?

Reading this post about the controversial decision to delete posts on Boing Boing and the fact I just made a post I've had to edit several times based on people's comments got me thinking about (EDIT :)) editing blogs.

Here I'm talking just about personal blogs like this lj, not proffesional or semi-profesional/famous ones like Boing Boing.

EDIT (heh): My brain turned to mush just as I was finishing this, so I'm still not going to express this well, but: I've conflated "What you do personally" with "What you tend to think other people should do" and "what you think is an objective minimum standard for blogging", and of course these are not always the same thing (such an objective standard may not even exist). Also I should make it clear that while I do think there are certain basic standards of behaviour I would expect from most bloggers (e.g. not changing your posts and then lying about it) on the whole I think people have a right to run their blogs how they like (though I think it's good to make your policy clear if there's confusion)

( When is it ok to edit a post? )