We filed my husband's N-400 in October of last year and received his interview date around January for February 12th. It was a combo interview because the Removal of Conditions was taking too long (got the 48-month extension letter) and he had already been eligible to file for citizenship for 6 months at that point so we got tired of waiting.
I had to be present for the interview since they also checked our Removal of Conditions paperwork and asked me several questions about our marriage. Afterwards it was on to the Citizenship interview portion and they also asked him the questions about American history, which he passed. The lady doing our interview was very nice and helpful, and afterwards told us he was approved for both Removal of Conditions and Citizenship! We waited to be notified about the oath-taking ceremony and he received a letter to attend the big ceremony last week on March 27th, which we were excited about because it means I got to attend with him. It was a long ceremony but it was the perfect capstone to our long immigration journey together!