“We’ll develop the device, then we’ll test it.”

Do this, and your project’s timeline will explode.

As product developers, we often fall into the trap of thinking “first we’ll build it, then we’ll test it.” After all, how can we do high-level testing until we have a complete prototype?

But in my book “Prototype to Product: A Practical Guide to Getting to Market,” I identify this mindset as the first of the “11 Deadly Sins of Product Development.” Putting off serious testing until late in the game is a surefire way to get blindsided by issues that require major rework.

I’m not just talking about basic functional testing, but the rigorous system-level and user testing that validates our core assumptions:

• Does the product work smoothly as an integrated system in real-world conditions?

• Is it truly meeting user needs and expectations?

• Are there usability issues or missing features that will limit its appeal?

Finding problems in these areas after we’ve already invested heavily in development is painful and expensive. We may need to:

• Redesign hardware to improve performance

• Rearchitect software to enable new features

• Rework the user interface to resolve usability flaws

All while the clock is ticking and launch deadlines loom ever closer. The solution? Adopt an iterative testing approach from day one:

1. Identify your riskiest assumptions and most critical user needs
2. Devise experiments and prototypes to test them early and often
3. Incorporate learnings to evolve the product design
4. Repeat until you converge on a rock-solid product

Yes, this takes time and effort. But it pales in comparison to the costs and delays you’ll face by leaving testing until the eleventh hour. In product development, the old adage holds true: an ounce of prevention is worth a pound of cure. Prioritize early testing, and you’ll thank yourself later!