The date on the package doesn't take into account your soil, weather conditions, or rainfall. You are a better judge of when to pick. We have Contenders, too (and by the way, congratulations on choosing one of the best bush beans!). When the green beans are as big around as a pencil or slightly smaller, pick. The smaller beans are more tender and flavorful. You are in for a taste treat!
You didn't ask, but be sure to pick only when the plants are dry (not dewy or rained on) and pick about every other day--beans come on fast!

As Marlingardener said, don't worry about the days to maturity.

There is no such thing as an unripe bean so they could be picked at any size including 1/2" long. Of course that would be kind of silly, but they would still be very edible.

The only thing you want to avoid is letting them get too large/old as green beans then tend to become tough and fibrous.

Just pick them when your eyes say they are a good size compared to what you are used to seeing in the stores.

Yep. What they said. It also wouldn't be a bad idea to leave one bush unpicked, maybe at the beginning of the row/bed, to learn what overripe beans look & taste/feel like. If you let them go all the way to drying on the bush, you can save them for planting next year.

I always leave my beans for dried after I have picked for several weeks. I plant 3 crops about 3 weeks apart, so when the 2nd crop is starting to produce well, I stop harvesting the first and let them become my dried beans for soup. Then same for the 2nd & 3rd.

For dried, just let the beans grow to maturity, then the plant will start to die, the pods will turn brown, when they are crunchy and dry you can harvest them and shell them for soup.

That's a relief. For some reason I thought they had a narrow window where they developed their flavor suddenly.
I know individual results will vary but how long will a single plant continue to produce if I keep picking the beans before they dry?

drayven

Pole beans produce many weeks, while bush beans produce all theirs in 2-4 weeks. (It's sort of like the difference between indeterminate and determinate tomatoes!)