Always be ready to ask the interviewer questions.
Timing is key.
Appropriate vs. inappropriate questions. This is the wrong answer. You have passed up your opportunity to ask some critical questions that may make a difference as to whether you want to work for this company. When Marianne was asked if she had any questions at the conclusion of her first interview, she began asking about sick time and vacation days and when she would be able to start taking them. The interviewer was taken back.