I’ve worked on projects at various stages of maturity, which call for different approaches depending on product-level priorities. These stages blend between one another, are often iterative, and the projects I’ve been exposed to have defined their phase segmentations differently, but here’s a generalised overview:

Conceptualisation & Definition

Proof-of-concept Prototype

Early-stage Prototypes

Late-stage Prototypes

Start-of- / Post-production

Product Development Stages

- Searching for product market fit
- Primary and secondary research to scope end-customer needs
- Ultra-low fidelity prototyping to demonstrate design intent

- MVP: defined product category and value proposition(s)
- Gathering feedback from early adopters
- Quick iterations with rapid prototyping and off-the-shelf components

- Early low-volume testing (engineering validation tests)
- Soft-tooled parts
- Top-down analysis: requirements listing and system decomposition

- Detailed function and manufacturing de-risking (design and production validation tests)
- First-off hard-tooled parts
- Pre-production sample runs
- Bottom-up tests: verification and integration

- Change management for mid- / post-manufacturing updates
- Detailed optimisation for cost-down and reliability factors