There are a lot of small businesses out there operating as sole proprietorships, that is they operate the business through the individual(s), and there is no formal entity. Many sole proprietors tell me that they’ve filed a d/b/a with the local county (here, the counties of Onondaga, Tompkins or Monroe), and therefore believe that is all they need to ensure that they are not personally liable, but this is not correct.
The main reason people incorporate or organize LLCs is to limit liability. Debts and contractual obligations are not something that you want to owe personally if you can avoid it. Setting up an LLC will create a seperate legal entity from yourself that you will operate the business through, own business assets, and contract through. Not much has to change when you form a single member LLC. LLC’s are also useful because the IRS will let you choose how you want the LLC taxed (either as a disregarded entity, S corp or C corp).