In some cases, it might make more sense to buy a blog that's already been around the block for a while. The devil (as always) is in the details, however.
If you've found an existing blog in your desired niche that's already getting some traffic, maybe generating a little revenue and you have the investment funds to allocate toward acquiring the site, then getting your hands on a blog that already has traction can be a great way to avoid a lot of the more technical bits of learning how to start a blog. That's not to mention giving yourself a chance to leapfrog a lot of the early hurdles that come along with build a reputation for a brand new blog.
If you're considering going down the route of acquiring an existing blog, check out my guide to buying a blog today.