  Soft limits of inflationary correlation functions are both observationally
relevant and theoretically robust. Various theorems can be proven about them
that are insensitive to detailed model-building assumptions. In this paper, we
re-derive several of these theorems in a universal way. Our method makes
manifest why soft limits are such an interesting probe of the spectrum of
additional light fields during inflation. We illustrate these abstract results
with a detailed case study of the soft limits of quasi-single-field inflation.
