Many posts I read are filled with information, perhaps pictures were added to make it eye pleasing, and of course it was formatted for easy reading. Clearly, you are putting your best foot forward for your readers. After all, your readers are going to choose to do business with you because of it, right?
That being said, why do you not retract a post that is no longer valid? Keep in mind I am not talking about the posts that are based on opinion or experience. I am strictly talking about factual data that has since changed and/or were just incorrect to begin with but someone provide you with the correct information within a response. I know I know.. it takes time to make the corrections and perhaps an updated post will come... eventually.
So, why do I care? Well, I like for the buyer or seller to have the correct information. Its bothersome to read some posts that have incorrect data. And even after the blogger was told about the error, it was never corrected. Sure, they acknowledged the error within a response, but what if your reader does not read all of the responses? Should you not make an adjustment to your original post with the correct information? Don't you want your readers to know they are working with someone who KNOWS the latest changes? I still come across posts that talk about the $7500 tax credit. Really? Why haven't you updated that older post with a link to a new post which talks about the $8000 tax credit? After all, the newest guidelines are more pleasant to read (no repayment plus more money).
Take the time to make the corrections. Don't delete the previous post, but take the time to add the corrections and a link to the newest version/post. Not only will that clear up confusion, but it will also provide some 'link love' which GOOGLE loves. Win Win!