4X — Explore, Expand, Extract AND Exit

Kent Beck’s 2016 3X model (Explore, Expand, Extract) is essentially a different way of expressing Theodore Levitt’s 1965 product life cycle (Market Development, Growth, Maturity, Decline).

1. Market Development → Explore
2. Growth → Expand
3. Maturity → Extract
4. Decline → ?

For the missing X for Decline, I propose “Exit”.

In other words, the 3X model becomes 4X: