I'm not a guy, but I thought I would chime in. I definitely prefer planned appointments over spur the moment appointment, but I try to keep myself readily available for those last-minute guys that do not plan ahead, which can be difficult at times being a student. One of the biggest reasons I prefer preplanned is because I love having the anticipation of the date. It gives me a lot of time to get ready, and if they have a preferred 411 account that they have taken the time to fill out, I have some insight as to what they do and do not like and I am able to plan better, therefore making the experience better for both of us. But there is something to be said about the kink factor of the last-minute appointment.