Dynamically adaptive systems (DASs) change behaviour at run-time to operate in volatile environments. As we learn how best to design and build systems with greater autonomy, we must also consider when to do so. Thus far, DASs have tended to showcase the benefits of adaptation infrastructures with little understanding of what characterizes the problem domains that require run-time adaptation. This position paper posits that context-dependent variation in the acceptable trade-offs between non-functional requirements is a key indicator of problems that require dynamically adaptive solutions.