Biologically the larger the crappie, the less time it has to live. Most crappie do not live much past 5 years. Some will live 8-9 years but they are generally the slow growing ones. When a crappie reaches lengths of 13" or larger in Missouri, it's on it's way out. It will have already contributed the majority of its genetic material to the fishery. I always recommend keeping the largest crappie since they are nearing the end of life and toss back the smaller ones. But that being said, my preferred size is 10-11" for eating. Many anglers envision crappie fishing like some of the Mississippi lakes here in Missouri and it's simply not likely. The Mississippi lakes are very infertile. Shad growth there is very slow. Shad in MS can be eaten by crappie for a year and a half before they get so large only the biggest crappie can eat them. In Missouri's fertile lakes, the shad grow too large in 4-5 months. Add in the almost year-round growing season in MS and they have conditions we can't duplicate. The 10-11" fish still have time to grow larger, the 13"+ are running out of time.