I grow runner beans on my fences and eat young green beans all summer/autumn,
freeze, give away and ferment lots,
and there's still
loads on the plants.
I leave them on till the pods are brown, then pod them, leave the beans to dry thoroughly and store in jars.
The roots are perennial in my climate, but production is supposed to go down as the plants age.
I poke in more beans every year to make sure that's not a problem