Bush beans, which all come to maturity about the same time, are ready for harvest in 50 or 60 days. Pole beans take a bit longer, about 60 to 70 days.
Harvest beans while the pods are young and tender and the beans inside are still immature. Pick them before the swelling beans are visible as bumps on the pod surface. If pods are too old they get tough, and (in some varieties) develop strings along their seams.
Important Pick all mature pods even if you are not able to eat them. This will keep the plants producing more beans; leave the beans on the vine and the plant will stop producing. Bush beans will continue to produce for 3 weeks if kept picked. Pole beans will yield all season long.
If pods do have a chance to get overripe and tough because you could not get to them, allow them to dry on the vine and harvest the beans inside for dried beans.
Storing - Store freshly picked snap beans in the refrigerator in plastic bags. They will stay relatively fresh for a week or so. Snap bean pods will keep in the freezer up to 12 months. They can also be canned in a pressure steamer or pickled.
