One way to bring more spontaneity into life is through variety. Variety is the spice of life, because it can be fun and inspiring. Whether it is a vacation, a new kind of food, or a new sweater. However, if we have variety without any repetition or repeated structure then we become unstable. Like traveling without a home or wanting new things all the time to such a degree that we become financially at risk.
The synthesis of a repeated structure and variety creates a feeling of being secure and expansive. Another way of talking about this is the synthesis of discipline and spontaneity. So create systems and exceptions to the rules. The systems create ease and security and the exceptions bring the variety that is the spice.
Examine your life. Do you have a nice balance of structure and variety?