My plan for my garden is to provide enough for my family not only for the gardening/harvest seasons but for the rest of the year. So I wil be planning on a garden large enough to can some of the harvest - my children love fresh vegetables.
Going by the general knowledge available on researching the web, I decided to look at beans. Since I live in an area with a very short growing season, I don't do dried beans, yet. Beans come as bush or pole beans. Bush beans have a shorter time to yield while pole beans take longer. There isn't a whole lot of difference say for Blue Lake - 58 days for bush or 65 days for pole beans. I do bush beans because I have had good experience with them and little with the pole beans due to the high winds in my area.
The productivity seems to be much in favor of pole beans. They yield almost twice as much per plant as a bush bean does. The average given for plant per person on the web is 10 plants. But if you get twice as much from a pole bean as from a bush bean, you need to take this into account. In checking gardening forums I found that one garden said they had a yield of 6.4 lbs of beans from a pole bean plant while the average for a bush bean was 3.33 lbs. If you planted 10 plants per person of the pole beans, with the average serving of 4 ounces (with 16 oz in a pound), you would be able to have beans as a side at 256 meals in a year (calculation would be 10 plants x 6.4 lbs x 4 (4 servings per pound)). If you did it this with bush beans it would come out to 133 meals in a year. So it depends on how much you like beans what you would plant. Green beans are a big favorite in my household, so I would be safe in planting more of the bush beans as I would not have as much to harvest.
Research yields on the variety of seeds you choose for your garden and take this into account when choosing how much to buy and plant.
Here are the general guidelines for plants per person.
5 brussel sprout