If you have "tight deadlines," you are not working with agility. First, unless the deadline is real (e.g. tax filing deadlines and an accounting app), it simply should not exist. Made-up deadlines are a form of bullying, and there's no place for that in an effective work environment. Next, even when the deadline is real, we handle it by working small, releasing often (every few days max), and always doing the most important things first. By the time you get to your deadline, all that's left to do is optional trivia. Artificial deadlines or even "commitments" to squeeze more work out of people fly in the face of the sustainable-pace principle. Look at Menlo Innovations for an example of doing it right (read "Joy Inc").