This is a great question! The short answer is:
You don’t have to cast a circle every time you cast a spell. The circle will give you confidence and a place to practice without distractions, but it’s not always necessary. Think of it as a “safe space”, your training wheels. Eventually you don’t really need it and it’s also good to experiment without it.
You can read a bit more about it here: Keeping your circle safe
There’s some more information on calling the quarters into your circle here and here.
There is no hard-and-fast rule on when to cast a circle. Many Witches don’t cast circles at all so don’t feel like you must do it everytime. Others only do it when working in a group, for example.
I cast a circle when I feel the work I’m about to do will raise a lot of energy. The circle helps to contain the energy so it doesn’t drift off in all directions. Another time is when I want to feel safe and protected, I simply visualize a sphere where nothing can come in.
When creating a charm bag you don’t really need a circle. But if it’s a protective charm, for example, you could follow along the circle of protection meditation and:
- Visualize protective energy around you.
- Charge your amulet with it.
- Whenever you need to, hold your amulet to invoke that feeling, that circle of protection instantly.