I am fortunate to have a faculty job at a great public R1 university. Owing to the high research activity, there is always someone here to give a talk. There are three seminar series, associated with three departments, that I usually attend (generally biweekly), and another 1 or 2 where occasionally an interesting seminar comes up. (Which begs the question: what’s the ideal seminar attendance frequency? Too many, and you infringe upon your work time, too few and you start getting out of touch, missing potentially important info about trends somewhat removed from your immediate expertise, which is where juicy inspiration for new projects comes from!)
On top of that, we are interviewing for multiple parallel searches, so we have been having 2-3 guests every single week over the past few weeks. Considering that I am involved in the search, I am supposed to not only attend each talk, but also formally meet with every candidate as part of the committee. And let’s not forget that candidates have to be taken out to eat, several times per visit. I know I am supposed to enjoy department-sponsored meals at nice restaurants and the chance to talk to smart new people, but I am mostly just resentful. My family doesn’t care for me repeatedly staying out and disrupting their evening routine either.
The face-time fatigue during interview season is brutal for job seekers, but if it makes you feel any better, it sucks pretty fiercely for the people on the other side who are involved with the search. As exciting as the prospect of bringing in bright new colleagues is, all the meetings and chit-chat and the extra seminars are simply… exhausting.
Good luck to all who are interviewing! If an interviewer dozes off or their eyes start to glaze over, don’t take it personally.
xykademiqz 
You have my sympathy! Very early in my tenure-track career, my department had a “perfect storm” sort of thing where we were filling several tenure-track positions at once. We had just enough tenure-stream faculty to make up a viable committee and did 8 campus interviews in a 3 week period, including 4 in one week. (Plus one or two before/after that intense period.) One hour teaching demo, one hour research talk, lunch, dinner, individual meetings, committee meeting with the candidate, committee meeting without the candidate, facility tours. Five to eight hours times eight, and none of us could really miss anything unless it conflicted with our class schedule. Exhausting, especially the face-time aspect. Basically everything you said. But, I still have two great colleagues out of that search!
Recruiting season is tough. We just finished doing 6 interviews in 2 weeks (during the last week of instruction and finals week, which are already hectic times). One of the interview talks was scheduled at the same time as lab rotation talks for students in some of the faculty labs (most of the lab rotation talks were on the day between two recruiting talks). I went to 5 of the 6 dinners and had one-on-one talks with all 6 recruits (and I wasn’t on the committee).
Under normal circumstances, I find that one research seminar a week is about the right number, with an extra one tossed in occasionally when a particularly interesting topic pops up in a series I don’t usually attend.
Still, I prefer 6 interviews in 2 weeks to one a week for 6 weeks—it is a lot easier to compare people when you see them all in quick succession than having to remember details from over a month earlier.
The Brits have an interesting way of doing this. They bring in all the candidates for a couple of days and pass them around the department. Sometimes they do this at a retreat.