Products do not go from idea to market in one motion; they move through recognizable stages, and each stage exists to kill bad versions of the idea cheaply before the next one gets expensive. The cycle is a filter, not a conveyor belt.
In this glossary topic:
What is the product development cycle?
The product development cycle is the full sequence a product moves through on its way to users: research and discovery, definition, design, development, testing, launch, and iteration. The cycle repeats rather than ends, since post-launch learning feeds the next round of discovery.
What are the stages of the product development cycle?
Six stages recur across frameworks, whatever names a team gives them: discovery (understanding the problem and the market), definition (deciding what to build and for whom), design (making the solution concrete), development (building it), testing and validation (checking it works for real users), and launch with iteration (shipping, measuring, and feeding results back into discovery). Teams move through them with different rhythms, from strict phase gates to overlapping agile loops, and the stage names matter less than the decision each stage exists to force: is this still worth building, as currently conceived?
Why does the product development cycle matter?
A shared cycle gives teams common checkpoints: everyone knows what question is being answered now and what evidence moves the work forward. Without one, stages happen implicitly and out of order, which is how products reach development before anyone agreed what problem they solve. The cycle also makes risk visible, since skipped stages do not remove their questions, they just defer them to a more expensive moment.
