I’m not sure I understand your question, but as to how many words per post … use as many or as few as it takes to get your point across ;o)

Articles are generally a minimum of 300 words and a maximum of “Whatever It Takes”, but you can post just a quick comment of only a few words now and again if you like.

That is the beauty of blogging

As to how long you leave a post up …

The nature of blogs it that they automatically replace the last post with the new one, and depending on how you set up your blog, they either move the old one down, or archive it, so they NEVER really go away.

I personally like to have my blogs Archive the old articles as that gives me one article per page and I want as many pages listed as possible

Len