While many transactions can be handled in a straightforward manner, there are times when the assistance of a professional such as a lawyer or financial advisor is needed. Your REALTOR will often indicate when this occurs but even if they do not, remember, if outside assistance would make you more comfortable then take the steps to get the advice you want.
Even if it is not common practice to use an attorney in your area, it still remains your choice to do so if that is your preference.
I have bought and sold several homes throughout the region (all in PA) and never has an attorney been involved. Nothing has been particularly contentious, and my Realtor is VERY familiar with all the ins and outs of the forms, helping make sure I get what I need and understand my rights. I honestly do not know what an attorney would have done if we involved one (except bill me thousands of dollars, I am sure!)
A good Realtor is a great asset.
Commercial transactions are different and their are lawyers that deal with commercial transactions frequently.