You may want to keep certain dungeons around if you find they have a useful farming spot, a place of interest you want to preserve, or you left some side areas behind to explore, but otherwise, there is no harm in clearing space for new chalices. When should I be doing the dungeons ...
of which you can usually hold 20 at a time, and store 99 others in your stash for safekeeping. Some enemies drop vials when you slaughter them, but Hunter's Dream holds an infinite supply for purchase, so you can go farming for blood if you like, though it isn't strictly necessary. ...