Unfortunately, I read your posting after your day of "serial interviews."  A few weeks ago, I had a full 7.5 hour day of interviews, 8 interviewers, and a lunch "break" with one of them.  It was rigorous.  I had to be "on point" during lunch since it was also part of the screening process.  Overall, I thought I did well; there was one individual, however, that was a tough sell.  Her job was exactly what I did for my previous employer for 6 years.  She asked if I would be happy giving up that sort of work, stating that she would never want to quit doing that job after 30 years.  Although I felt I responded appropriately, I left feeling as though she would be my toughest critic.  I am not sure whether she perceived me as a threat or not.  The position for which I was interviewed was closely related, and I know I was highly qualified.  Several days ago, I received the dreaded "we chose another candidate" phone call.  After absorbing the rejection, I called the manager and left a message asking for feedback, positive and negative.  He never responded.  After my day of interviews, I realized that I need to resume, after several sedentary years, a regular exercise regimen.  Years ago, when I prepared for the California bar exam, I not only studied, but also prepared physically for the 3 day exam.  It paid off, I passed it the first time.  Now, although my weight is fine, I have allowed my physical fitness to decline, and after that long day of interviews, I realize that I need to increase my stamina to sustain the level of energy needed for future interview trials.  Don't get me wrong, I am quite fit for a "normal" day of work; however, the stress level of interviewing takes a much greater toll than a 10-12 hour workday.  

I am currently awaiting word from another employer with whom I interviewed.  The position is exactly what I did previously, the organization is affiliated with the one that turned me down.  At the age of 52, and 3 years, 9 months of seeking employment, this job is virtually life or death for me.  I reside with friends, because I cannot afford housing and have no health insurance. They have a full house and need the space I am in.   Although I am in overall good health, I have some medical conditions that require treatment.  (primarily, treatment/pain relief for arthritis that has plagued me since my early 20s)   

BTW, I was not terminated from my previous job, but resigned to take time off to spend with family following the deaths of my father and the unexpected losses of 2 other family members and one of my best friends.  Had I known I would become "unemployable" I would never have resigned.