As a veteran of product development, I’ve seen my share of projects succeed—and fail. In my book Prototype to Product: A Practical Guide to Getting to Market (O’Reilly), I identify 11 common pitfalls that can derail even the most promising efforts. I call them the “11 Deadly Sins of Product Development”:

1. Putting off “serious” testing until the end
2. Assuming we know what users want
3. Assuming users know what they want
4. Lack of comprehensive requirements
5. Lack of a good project plan
6. Not assigning responsibility
7. Not addressing regulations
8. The sin of new-feature-itis
9. Not knowing when to quit polishing
10. Not planning to fail
11. Developing technology rather than products

These sins fall under five main “vices” I see plague many projects:

1. laziness
2. assumption
3. fuzziness
4. perfectionism
5. hubris

Recognizing these pitfalls is the first step to avoiding them. In upcoming posts, I’ll dive into each of these sins in more detail, sharing real-world examples and practical strategies to keep your product development on time and on budget. Whether you’re a startup founder, product manager, designer or engineer, understanding these common failure modes is essential. Because in product development, what you don’t know will definitely hurt you—and your project.