It can be exhausting to go through every day guiding a young child this way and that way, moment by moment.
When you develop a routine it will carry the whole family and the child quickly learns what is coming next which supports them to go with the flow.
By setting a routine you are deciding ahead of time, with your partner and any other caregivers, what your limits are and where they lie.
This way when something unexpected comes up, you are supported by this framework.