If you go in the mornings anywhere from 7-11am, it's usually not that bad Monday-Thursday. Don't even try Saturday. Friday can get pretty busy as well.
Good question! Lines can be really long because of people needing to renew in person to get the Real ID, but the best idea is to arrive as early as possible so the wait will be shorter. You can check on appointment availability, but it's not necessary and they can be booked pretty far out.
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