Your experience with blogging/seo?

I'm looking into SEO as a marketing strategy. Being relatively new to blogging (one part of my SEO plan) I'm wonder how many you put out and over how long before you saw a return on your time-investment.

From my understanding it takes 6+ months as an average before google really starts pushing it for you. Also, I should be putting out 3-5 x 500+ blogs a week.

Any info on your experiences would be great. 😄