There are many persuasions on the net whether frequent content changes are good or not so.
Unfortunately there is no straight answer for this, as it looks the search engines (SE) operate differently for the different domains.

The massive belief is that the SE like fresh content and frequent changes to a Web page helps to raise its rank. Probably it is true for old “trusted” domains with already gained ranking, making reasonable changes. Even there are tools provided by the SE about creating sitemaps, where you can set how frequently you are changing your site.

On the other hand, trying to stop the search engine results page manipulation, the SE (especially Google), are switching between newer and older cached content and often this is causing visible search engine results page changes.

Personally I have experienced good ranking for some pages with daily changes, and for others such changes caused negative effect pulling them down in the listings for a particular keyword.

This can happen even with minor optimization changes, as well as when you just edit something on your page. I am not talking about alteration of thousands of words, but just 2-3 in a text of about 600 words.

Let mi give you example with our home page which is changing very often.

The above image is showing the entrance keywords for our index page in this month 1-29 MAY.

The next is showing totally different keywords and the reason is only the frequent changes.

Almost nothing in common. The onlinehowto.net words is there because of the SEO tools we using.

Let see one more month back of frequent changes.

The top keywords again are different.

In general too frequent changes on a page most probably will cause negative effect, at least you will loose some keywords already “assigned”.
For example on our home page, there is almost no text sitting there more than a week and the result of that is frequent changes of the keywords landing there.

While speaking for frequent changes, I mean not only about the text modifications. Another thing that affects search engine results page is frequent change of anchor text in your links. This is Google patent and it is definitely considered as bad.

Dynamic pages are not hearty welcome as well. At least if the session ID is changed, there is no way the page to be considered as one and the same.

What I can tell for finish is: Do not make optimization changes unless you absolutely have to. Changing links and pictures is not so harmful.

With this tutorial we close the line about negative on-page search engine optimization factors.