I Promise

If / when I am a professor, I will respond to e-mails from graduate students within 48 hours, especially if it seems like the sort of e-mail that the student might be anxious about. If I don't have time to write a detailed e-mail, or I'm not sure of the answer, I will respond with an initial reaction and a promise to write more within a few days. I will not keep students in suspense for 5+ days -- not because it's unprofessional or unreasonable to delay responding, but because I've been there and I understand.