Some years ago me and my gardening cohort planted some Danvers from Seeds of Change. We got lots of yummy carrots but left about 4 to bolt, which they did. After they dried we got hundreds and hundreds of seed, many of which we gave away. The next year we planted some and got lots of yummy carrots again. As did those who planted those seeds. We had so many seeds that I put them in tiny zip-lock bags and gave them to my friend who works farmer's markets. She gave them away - "Free w/ purchase." She said that a lot of people didn't even know that carrots came from seeds!
So, start with a good heirloom and let a few go, but do keep them away from Queen Anne's Lace. I've never heard of a 2nd year carrot anyway.
