No need for a lawyer
Namecheck,
FYI, I was never interviewed both 1st & 2nd time. I was told two different stories. Atlanta DO would tell me that my file hasn't transferred from TX so they can't interview me but on the other hand senator's office would tell me that USCIS is doing additional checks on me. I got really tired waiting for 18 months & finally filed law suit (WOM) and got my interview within 60 days. Took the interview and oath the same day.
You really don't need an attorney to represent you. If you had issues with your case, it would have been a diff story but if your case is straight fwd, just feel confident. Make sure you know your N-400 application pretty good & those 100 questions. Trust me USCIS interview is nothing but a joke. Everybody is able to pass the test.
If you take a lawyer with you, he or she cannot force to make the IO to make a decision on your case or grant you citizenship. To me it is just waste of money.
Let me know if I can be of any further help.