How important or unimportant is planning ahead?

How important or unimportant is planning ahead or sketching out pre-meditated ideas before you start working on your actual art piece? This is a question that my answer for has changed. Initially I would say no, planning ahead is not important. Intuition is how I'm lead especially when drawing in my sketchbook. This summer I have had the most failure when I haven't planned. As an example I purchased a canvas thinking I would create a masterpiece. The beginning of an idea was in my head, even though it was not quite clear. I took my paints, brushes and excitement thinking this was the moment. Squeezing paint onto the palette I began applying paint to the canvas. The end result was a colorful mess that made no sense. When others looked at it, a confused look covered their face. No one thought it was exceptional or even good. It interpreted as disjointed, uninteresting and without direction. My intent was the opposite of the end result. Later, I returned to my sketchbooks for inspiration and found sketches from a few years ago. I began re-drawing some of the sketches on larger sheets. These were viewed as visually exciting and interesting. The more I drew the more a story began unfolding visually. The story itself wasn't pre-planned but some of the imagery was. Building on that imagery with repeated shapes and spaces created unity that led to a unified composition. Each time I attempted to work intuitively exclusively, the end product didn't result in work of satisfaction. I've found that having the entire work pre-planned isn't necessary but having a sketch to work from as a starting point is more than helpful. I do allow for intuition to play a part in the development of the work but sketches provide direction and breathe