Over time, after a lot of study and becoming comfortable with your Craft, you will be able to design your our ceremonial pathways and become more flexible which will lead to being spontaneous. Your Book of Shadows is all important building to that point. In emergencies, I have designed what I call "Fast Track" ceremonies which can be done spontaneously, quickly, and effectively. One of the tools you need as a traveling Witch is a compass. Just a simple one without the damping fluid expensive ones have-which can be ruined through air travel. You need to know the direction where your spell will be needed. If you are in a hotel in a new city traveling you may not know where North is. Thus the compass. Being spontaneous takes time. That's where your Book of Shadows is so important. That is you log of everything you have done.
Beginning Witches may be hesitant in creating a ceremony. It is a big step!!! One actually takes hold and creates a Sacred Space. Again, that is why it is so important to have a Book of Shadows. Your Grimoire can be included or separate. It took me years to get to that spontaneous zone where intent is focused. That comes with being comfortable with your OWN ceremonial path, comfortable with your Sacred Space smoothly operating through a system you have created. I our society, people are used to having someone else conduct ceremony like through organized religions. Taking hold of one's powr takes courage and determination.