There's a difference between "have to hire" and "should you hire." As far as whether you have to hire, no. You do not have to hire an attorney to represent you. You can go it alone, and you can go through the entire process without representation. However, with respect to should, our office generally recommends that you hire somebody to represent you.
Statistics have shown that those who are represented stand a greater chance of winning their case, primarily because of the development of the claim, making sure that the evidence is complete, getting competing evidence from doctors, preparing the client for what to expect, coming up with a theory of the case. Those are all very important components of the case that having good representation can help you with.