AGRICULTURAL NEWS - Commercial beans are allowed to develop to their maximum size while still marketable, as this enables more beans to be harvested at the same time, saving the grower money.
However, the opposite is desirable for the home garden: you want to pick the pods as young as possible for tenderness, taste and nutritional value. In the process, you extend the harvest period and increase total yield.
A plant has one goal: to produce seed for the next generation. As soon as it has achieved this, it will stop flowering and even abort flowers and young pods. If you constantly harvest young pods, the plant will continue producing seed by setting new pods.