After a superday interview (6 different 30-min interviews), we usually decide who we want the day that they interviewed. We will call back our top candidates on the same day and offer them, and then call the others in the following days. Ideal candidate - knows technicals, is very personable and easy to talk to, can pass the airport/drink a beer test, seems like they actually want this job and isn't interviewing just to shop around their Citi offer or leverage it to get to another job.