I don't have office hours per se but students know that I have an open door policy and that they are free to drop by at any time that I am in my office. That said, few students do come to my office to ask questions; most seem to prefer emailed questions that are sent in the early morning hours. I can only assume that the students are studying, come up with a question and write an email on the spot rather than waiting for the following day when they can ask me the question in person.
I don't have any problem with this. Emailed questions are actually a blessing in disguise. I am not put on the spot to immediately answer the question but can rather think about how best to reply to maximise understanding of a concept.
However, it is a mixed blessing because it is much more difficult to convey understanding using only the written word. Think about that. In a live interaction the student can ask a question, I can reply and we can then both judge whether I answered the question fully -- the student has the opportunity to ask additional questions and I have the opportunity to clarify any further confusion that may have been introduced as the student contemplates my answer. Feedback for both of us is immediate.
In contrast, answering a question by email poses challenges. I write my reply and hit send. 99% of the time I do not receive a reply from the student and here lies the problem: did my answer satisfy the student's question or are they still confused? Did my answer raise any further questions that the student is not asking? In an attempt to remedy this I have started ending all of my emailed answers with a sentence along the line of "I hope that answered your question? Please do not hesitate to contact me again if you have any further questions".
The result? 99% of the time I still do not receive a reply from the students. Hence my current plea to medical students who ask questions by email: please take a few seconds to hit reply, type something like "thank you, that clarified my question" or, if it didn't answer your question/raised further questions then please let me know. After-all, if you popped into my office and asked a question then you wouldn't simply get up and leave the room following my reply. You would say something. Not sending me a follow-up email leaves me feeling that you have simply left the room and I am left wondering what just happened.
Please and thank you. It makes a difference.