It has often been assumed in theoretical studies of phonology that default rules (henceforth, DR) are classified into two types: those rules (α) that describe "purely logical" relationships among features and those (β) that capture "preferred configurations" of features. The argument that I advanced is that the form of type (β) DR is restricted to "A↔B in env. Q". The definition of DR interacts with the hypothesis on lexical rule application that in the lexicon DR cannot feed unmarked phonological rules, and it furthermore brings about significant simplification of phonological descriptions of individual languages (the term "unmarked phonological rules" refers to those rules that are unspecified with respect to their domains of application). I have dealt with three major phonological processes of German: (i) Nasal Place Assimilation (NPA), (ii) Fricative Assimilation (FA), and (iii) /ʀ/-vocalization. I have argued (i) that the distinction between the lexical vs. postlexical German NPAs and FAs is superfluous and (ii) that dialects of the Lower Rhine incorporate /ʁ/ into their underlying inventories of segments while Standard German takes /ʀ/ as an underlying segment.