You do not need appointment if do not take an eye exam, but there are certain times of the day, and week, when there is a lot of clients there, and you may need to wait a bit, but it's worth it :-). Usually more crowdy is during lunch time and evenings during working week, and also on weekends.
No, but you may want to call and check. I have walked in for an adjustment or to purchase accessories and no appointment was needed.
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