I didn't take a zero on my AT thru. Shortest day was something like 12-14miles. I took a 3 zeros on the PCT and hated it - My body doesn't know what to do when it's not moving (similar analogy is that the Tour de France cyclists ride 50 miles on their "rest day" during the tour so their bodies don't seize up).
I felt like trail culture expects people to take zeros, when in reality, there's no compelling reason to do so. I'm a solo hiker, so I move at my own pace. I'm also assuming you are not taking a zero for a medical issue (sprain/strain).