Years ago, Google used to wait a few months at a time before unleashing new search engine code into the world (wide web).
As it stands right now, they have teams of different programmers working on different segments of the search engine at all times. Some teams work on web spam filtering, some on measuring links, some on basic page formatting. Each team works almost independently of any other team.
As these teams release new features, they are automatically added to a daily routine of mini updates for website ranking. Most of the time you won't notice a big change in how your web page is ranking with the new features; in fact, you are more likely to hear about some change on a blog post than noticing it yourself.
However, there will be day when you sit down with your morning coffee and discover that your website ...