When I flew for the airlines, often I would be called to go on a trip with very little notice. What I needed for the journey had to be packed in minutes. Normally, the essentials were already in the suitcase and I only needed to add clothing appropriate to the destination. Without fail, I would forget some necessary item or items: everything from extra underwear, extra uniform shirts or socks. One time I left my passport in a jacket pocket when I left on a summer trip to Asia. Somehow, I managed to get by with what I had. So maybe the essentials really are not that important. What I think I cannot live without is, after all, optional.