The perfect set of initial ideas doesn’t exist. Everything needs to evolve and adapt to the environment. It’s always been that way: the only sure thing is that there’s no sure thing. In the same sense that a slow adaptation to the environment significantly reduces an organism's survival rate, an initial set of ideas mortgages the potential and the future of a project.
When we work on a new project, we start from an initial set of ideas that are, by default, prejudiced. Our prejudices model a system without taking enough variables into account. We start from a reductionist vision, far from reality, that lacks environment adaptation (t0).
In projects where the main objective is to add value (which is most of them), it’s the feedback that gives us the information needed to trigger adaptations to the environment. Cognitive empathy (being able to take the perspective of all types of users in our target audience) and being able to test rapidly are the engines that drive the feedback. They serve to model a new and more precise (and merciless) environment where the initial sets of ideas will fight to survive. Ideas will try to naturally evolve to keep up with the new environment. Sometimes, they will even mutate to unrecognizable forms. Don't try to stop it—enjoy the process. Ideas will come back to you, changed. And they will appear while you’re taking a shower; doing the dishes; in the middle of the night; when you are trying to explain them to others; while reading a book that’s totally unrelated...
That is the clearest indication that your project is alive and healthy, in the sense that it is resilient to environmental updates. And that means that everything will be fine even when it won't, because you had the best possible ideas given the situation you were working in. You might even find that your project doesn't make sense anymore, which is fine too.
In essence, don't just stick to the initial plan.
I found a perfect example of what I've tried to transmit here while reading the book "Zelda: Detrás de la Leyenda". Those who know me are aware without a doubt that I’m fascinated by Nintendo and its company philosophy. They are responsible for the oldest and most iconic videogame sagas in history, like "The Legend of Zelda" and "Super Mario." They achieved what no one else in the industry did: creating two sagas with more than 30 years of history, which are still examples of the highest quality in each console’s generation. They reinvent themselves with each title and seem to be immune to signs of wear and the conventions of the industry. This is because, in spite of the general objective being very well defined from the start (prioritize playability over everything else), the way they get there is based on experimentation and the constant search for what fun means.
It is fascinating to see the evolution of Nintendo in this respect through their games. This book describes how the directors of "Zelda II: The Adventure of Link” (1987), assessing the reasons for the title’s poor reception compared to its predecessor, admitted that the main reason is that the initial set of ideas barely evolved from the time of their conception. This is something they don't usually allow to happen. But this time, they stuck to the initial ideas just for the sake of doing it, which caused forced situations and a loss in quality that directly affected how the title was received by users.
Another fascinating company on this topic is Apple. One of their core values is to subjugate every idea to the most merciless environments and a holistic pressure on every aspect of a product (even those not perceived by users). The result is the creation of technological diamonds in every generation, which guide the innovation of the whole industry. Steve Jobs's official biography is full of history and good examples of this way of thinking and acting. A totally recommended read or listen.