No matter how long are you have been living with your head detached, carrying it all around completely exhausts you. Sally's case is unique - her head cannot be reattached due to a rare condition called Arecompono. It's characterized by inability to reattach a detached body part. This condition is often confused with another reattachment inability - Dysredo, characterized by inability to keep the part attached. Modular Collars help modular people keep their modular joints closed, protecting the body part from detachment of any form. These collars come in many different shapes and sizes to fit any body part and help people with Dysredo or other modular disorders. Meanwhile, Arecompono has no known cure, as in this case not even a brief attachment is possible due to the modular joint malfunction.

https://www.deviantart.com/faceithead/art/On-a-way-from-work-1159668355