I'm a field tech, so I often spend several hours a day driving around to or between jobs. I'll usually bring along a unit with a spare battery and a bottle of juice. For example, my Protank-2 mini on an Ego, with another Ego battery and juice. Or, the KBox/Plume Veil with a spare 18650 (and juice). If I'm just out running errands I'll get by with just a fresh battery and topped off tank, but if it's a dripper I need to bring juice anyways.
As for vacation...last year I took my whole kit with me (a small craft box with adjustable dividers) for rebuilding. This year I didn't want to bring that, so beforehand I pre-built all of my tanks (2 EVODs, the Protank-2, PT-2 mini) brought all my Ego batteries, the KBox, all my 18650s and the Plume Veil. Somehow all the tanks failed catastrophically before I even made it out of New York (on a 6 hour drive to Baltimore) and I ended up using the Plume Veil the whole time, only re-wicking once. With complimentary hotel cotton balls.