What are the common pitfalls and challenges of prototyping?

Prototyping in hard tech can initially seem daunting, but with the right approach, it can be a potent tool for innovation. One of the essential aspects of prototyping is embracing agile iterations; creating quick and simple versions, testing them, and improving them based on user feedback. By failing fast and learning from your mistakes, you can discover unknowns and refine your ideas quickly. At this early stage, it's critical to focus on user stories and define your minimum viable product (MVP). The MVP should answer the fundamental question of whether it's worth pursuing the idea further. By focusing on user needs and rapidly iterating, you'll be able to create a product that truly meets the needs of your target audience.

There may be many reasons for developing a prototype and there are different types or levels of sophistication of prototypes depending on the need. Prototypes of a plastic injection molded product for example may be to demonstrate functionality, material selection, design and costs trade-offs, etc. For electronic and mechanical products, a prototype may be necessary to test functionality and to tweak component selection and specification. In all cases, one should evaluate products with respect to Design for Manufacturing (DFM) principles. Slight design changes could result in less expensive or more available materials or result in less handling or manufacturing on equipment that is easy to adapt to the new product requirements.

Prototype development and the very purpose of prototypes are to be taken with a pinch of salt. Prototyping never follows the actual product development cycles. Hence the outcome is only to show and tell your story to those who cannot peep into your mind. It is just a marketing tool for getting the word out, partial aid for funding, generating enthusiasm in the team, creating the buzz. Most commonly, the prototype development does not consider the final product features. Component selection for the design, manufacturability, testability, feature addition, cost of end product, aesthetics of the product, serviceability of end product, and many more things are overlooked in prototype development. To cover all this in a prototype is tough.

Another consideration is whether the prototype exists as a complete stand-alone (e.g. something built in a design/mockup tool like Figma) or whether it exists within your app itself, perhaps in a staging environment. If building a prototype (a new feature, a major re-design, etc.) within your product/app itself, it is important to consider the trade-off between prototyping quickly with "hacky" code vs. following standard best practices in your codebase. IMO, finding middle ground is important, because it can be great to just ship it with a few small tweaks rather than having to re-write the entire thing the "right" way. While writing "hacky" code for prototypes can be tempting and is sometimes necessary, it isn't always the best approach.

It should be clear from the start what a prototype is for. Is it to show investors, to get user feedback on the ergonomics, or to de-risk some technical factors? Prototypes will be at best over engineered, at worst useless, if there is not a clear, agreed rationale in place for why they are needed. If a prototype is there to answer a question, then it should be borne in mind that the answer, not the physical prototype, is the goal. (And hence should be the explicit deliverable everyone has signed up to). If the answer emerges before the prototype is complete, or it can be determined analytically, the prototype is no longer required. The goal is to get the answer as rapidly, and cost effectively as possible.

The most dangerous notion I have seen with prototyping is confirmation bias. It is human nature to see events or objects in the light most favorable to our beliefs or desires. That is why clear, quantitative objectives are important. Another common error is testing two modifications on a product at once, blurring the resulting test data.

Prototyping is to be considered a temperature check of current and future product improvement and potential alternative routes to your product direction and maturity. It is not perfectly tied to the final product but it defines paths of possibilities. Should be done continuously and following a plan which gives priority to tech that increases the gap from competition. Make prototyping you ally not just another activity to do.