Go-Bag, Deployment Kit, Fear-Gear, etc. Whatever you call it. there are several items you should have with you during any deployment or activation. Preferably, they should be packed into a kit, a box, bag, briefcase, whatever, kept in your vehicle or ready to grab and go from home. Here are some ideas for what to have in your kit: Greene County (Ohio) ARES has a list of suggested items on their Jump Kits Page.
This page on Emergency Communications Lessons Learned in Hawaii covers training and mental preparation in addition to equipment.
The most important item to bring with you to an event is:
A POSITIVE, FLEXIBLE, MENTAL ATTITUDE.