Contacting a potential PhD advisor I am a senior who is graduating in December 2020. In May, I contacted a potential PhD advisor at my own university, and he was interested enough to offer early admission (in Spring as opposed to Fall). It took the professor 2 hours to respond.
I emailed him 4 days ago about confirming the offer still existed, along with the possibility of starting research in Fall (why not get a good start?).  If he does not respond for another couple days, would it be appropriate to do a &quot;walk-in&quot; during his designated &quot;office&quot; hours? I don't expect him to immediately reply, however I am a bit anxious to make sure everything is good-to-go.
Yes, if you have the opportunity to visit for a few minutes in person, you should do that. Ask if there are any further steps you should immediately take.
For an email reply, a few more days of waiting is better, but a quick visit is likely fine. Express your excitement about the future, etc.
In these perilous time, few now have the opportunity to do this sort of thing in person, but it is the preferred way. And, your situation isn't very typical since you probably already know the person and you are an &quot;out of cycle&quot; applicant.