"What if we build the wrong thing? Is that just wasting money?"

Small commitments are exactly about avoiding that kind of waste.

You are going to build the wrong thing at first. Until you actually put it in front of a real user and get feedback, everything is a guess. There's nothing wrong with accepting that this is the risk you're taking.

What to Avoid

What you don't want to do is build something very large and very complicated without a clear need and direction. That is waste. That's what we're trying to avoid.

The Boat vs Car Analogy

Sometimes you'll realize you built a boat when what you really needed was a car. At that point, the way I think about it is simple:

It's easier to build a car than to turn a boat into a car.

So don't get attached to the code. Don't get attached to parts of the project that don't work.

The Real Question

No matter what's happened before, the question should always be:

"How do I get to where I need to be in the most efficient way possible, with the least waste?"

Sometimes that means throwing code away, and that's fine. The bigger problem is throwing code away because we never showed it to anyone and we were just guessing for months.