Along with a broad trend toward lower spectral index with increasing gravity (age), there is an ∼±1 spread in the spectral index at any given log(g). While the classes are often assumed to be an evolutionary sequence, there are Class I, II, and III objects of the same age, showing that the amount of circumstellar material varies widely at any given time. The dearth of targets between the Class II and III objects is likely a selection effect, because we chose Class II YSOs with massive disks.