I don’t think there’s any real answer to your question. Yes, search engines like “fresh” content, but search engines don’t update their indexes every day. Every blog post has the ability of being found by SE’s, so updating / adding new posts will not guarantee Google, or any SE, will “like” your post. I know of blogs that have a new post every day that don’t rank well in Google. I know of blogs that have a new post once or twice a week and rank within the top 30.

You need to update your blog as often as you think your readers are interested in what you have to say. Just make sure to have your keywords and key phrases incorporated within your blog posts – in a manner that still reads well – and the SE’s will find the posts.