SEO specificna. It plays in Black Box Turinga. Imagine changing world of search algorithms, which, moreover, are tightly closed to the outside.
What would you do — have to work at random. Here statistics helps — the presence of an increasing amount of scattered information about different methodof promotion.
One employee more or less efficiently pulls 5-8 projects. Ie freelancer sampling sites 5-8 + feedback from peers on forums and community.
Have a SEO-company — between 50 and 800 projects, this is a representative sample.
With subsidence of the separate sites after update quite quickly becomes clear how to act.
Another downside of freelance is the lack of a closed automated software — that affects when working on a huge semantic kernels (more than 200 saprosma on the website).
And online stores can be up to 10 000 different queries (nizkochastotnoi) for the project!
Additional risks — the disappearance of the freelancer. All of the above relates to SEOs in the company, and to the little young SEO companies. + add the cost of your time that you spend on communication with the private master.
Conclusions: if you have a small SEM.the core of the low competition in your market, you are young and you have enough money — you can take the risk and hire an employee or freelancer for promotion. But, maybe you should try yourself? It's not so scary
In other cases, it is not a calculated risk.