No Such Thing as Overnight SEO?

As an SEO, how long does it take to see results? And as a business, how long should you wait to experience the benefits of that SEOs effort?

Google's recent " How to Hire an SEO" video discussed these issues (and others) and specifically how long it takes for SEO changes made to result in actual improvements.

In the early days of SEO, it was quite common to hear (and receive guarantees) that "optimization" could take just days or weeks to result search ranking improvements.
While it was true in some instances, the reality was (and is to this day) much harsher - it can take months to experience the impact (good and bad).

What has your experience been with SEO? Can you get a website ranking for competitive terms in months or in a shorter time frame? Share your experience with a comment below now.