USFS limits stays in Shelters to 3 nights per 30 day period.
Appalachian Trail Limits of Stay
The U.S. Forest Service has established new limits of stay regulations at all Appalachian National Scenic Trail (Appalachian Trail) shelters, as well as one campsite and two overnight sites within the southern region. Overnight stays at the three regional Appalachian Trail shelters—Davis Path and Davis Farm Overnight Sites and Wayah Bald Shelter Camp—now are limited to three days within a 30-day period.
Read more here (two documents)...