old adage was:A few years ago I went to a gardening meeting. An older lady, master gardener, told us to plant more than we need and to plant a variety of different crops. Some years one type of plant will grow better than others, and the next year it might be the opposite. You lose some goods to varmints, others to weather. So, just be thankful for what you get and try again the next year with lessons learned from this year.
one for the rock
one for the crow
one to die
and one to grow
I usually plant 4x what I need and hopefully get enough.