Our choices are becoming very clear, if we want to have a profitable blog. Especially when we choose highly competitive niches such as making money online, entrepreneurship or home based business. We have to be willing to invest serious time into building thousands of pages and that can take years to make happen, unless of course we pay someone else to build pages
That's why exploring narrow niches in specific marketplaces may be the best idea. A lower traffic area will often produce better results, especially given the fact that you need far less content to capture top attention and be recognized as a top expert in the field.
For me, my expertise is start-ups and entrepreneurship. I have done so many different businesses that to narrow and focus is not what interests me, and not what I'm about. That means that even though I am an expert in this area, I have to compete with a substantial amount of want-to-be experts on the subject and people have to take extra time to really figure out if I know what I am talking about, unless of course you know me personally.
Whatever your choice, you should know that to be considered at least a medium size site according to Google Webmaster Tools, you have be indexed with at least 250 pages of content. That means you probably need around 300 to 350 pages built of quality content.
Now that you have that information, you should be able to figure out how long it will take you to get your site to where you want it to be.