Plus you can't properly quarantine when you toss a new addition in with an established animal. QT is a MUST: do a search on that too for proper QT procedures. It helps keep your snakes healthy and safe and wards against costly vet bills in case you bring in a new animal who becomes sick/came in sick.

Plus (IMO) cohabiting should only be done by those who are experienced and not new to snake/BP ownership.