The freshness of your site only applies to search queries that require up to date information. If you have a movie review website, freshness is vital, if your site has how to install the suicide clutch on a Indian scout freshness is irrelevant.
If your niche does not require freshness, constantly changing the site will constantly hold down your rankings.
Imagine you are a search engine, and you look at a site that targets queries that do not rely on current information. You grade the site based on all factors, assign a ranking, and place it in the cache. The next time you come to the site, the information has changed, so you have to re figure out everything and cache it again.
If each time you go to the home page it has changed, the SE will never figure out what the page is about.
Typically a site will debut at rank XX, then rise. You are not giving the site a chance to rise in the rankings.
It may rank in spot one, but if it comes in at spot 5, it will fall out when you change it, because it is not the same page that ranked in spot 5.
Use your head, if your niche requires current information, freshness is vital, if not, it is detrimental.
Do not confuse changing the content of a web page with keeping your site updated.