I just wanted to clarify that the intent of whatever you use (circle/sphere, shield, intent) to create a sacred space is not just to keep out "evil", "bad" energy, or "ill-willed" beings.
One would not necessarily need to intend a negative outcome to be counterproductive to a working. If you don't set limits on who can help, you may get "help" you don't want.
Let's say you want to do a spell or ritual to improve the energy in your home. If Eris, Loki, or Coyote were to come and lend a hand, you'd end up with a lot of chaotic energy floating around. Yeah, it could "improve" things, but it would likely be going about it the hard way.
Better to only get the sort of help you need or want.
