In my sometimes-desperate searches for blog topics, I've seen a lot of 'experts on magic' say that you should never do magic unless you do it within a cast circle. I rather disagree on this point, and feel that for thaumaturgical magic - magic aimed at 'miracle working' - circles are totally optional. For theurgical workings it IS useful to create some sort of sacred space, circles being one common way of creating that. (Ivo Dominguez, Jr., goes into lots of ways to cast sacred space for Wiccan rituals in his book "Castings", if you want to look at those). Goetia, clearly, needs circles and triangles and probably demon-extinguishers, and Ceremonial Magick is, well, fully into ceremony.
That said, you might have notices that in both of my recent blog posts on doing magic The Healing Cauldron and Steak Sans Sizzle no circles were involved. In the case of 'steak', casting a circle would have taken away from the magic in several ways - first by drawing attention/odd energy from the rest of the folks in the store, second by being repeatedly violated by children running in and out of it. For my Cauldron work ... well, let's just say that I know myself. I'm FAR less likely to do daily work there if I add circle casting to the working, and I don't think that creation of sacred space would add much if anything to the work.
Tomorrow - what ARE circles and other forms of created sacred space good for?