Significant gaps persist in our understanding of chondrocyte biology. We don’t know when, how, or even whether these cells are replenished throughout the normal, human life span. We are taught that as much as 90% of the cartilage is “metabolically inert” interterritorial matrix, but we don’t know how this substance is regularly replaced (as it is known to be) by the distant chondrocytes, We recognize that the “tidemark” is the most conspicuous histologic feature within cartilage, but we don’t understand why that layer stains with hematoxyllin or what that may imply for the biology of the tissue. These, and other, issues may be clarified if the lifetime of each chondrocyte begins as a mesenchymal stem cell at the articular margin, plays out over years on an arcing trajectory along collagenous guidelines, and ends as an extracellular deposit of intracellular remains at the interface between uncalcified and calcified cartilage. This hypothesis is presented here and some of its potential implications are considered.