Why You Should Outsource Search Engine Optimization?
Outsourcing has a negative connotation due to offshoring. I, personally, find outsourcing to be a very good thing.
Mostly, the decision comes down to making money. This is true for search engine optimization work. If you buy articles, you can probably find them for less money than it would cost you to write them yourself (particularly if you are a slow writer, or if you draw a large salary).
If your expenses would be the same, however, then writing for yourself may be your best bet, depending on how much stress writing causes you.
As an example, I often buy articles from a handful of ghostwriters in order to promote my work. I treat ad and affiliate profits as fuel for buying more articles in order to boost my off-site SEO (in the form of targeted backlinks).
There are many services that will write for you, and there are also many services that will create link wheels for you.