How has the term "municipal affairs" been interpreted by the courts?

The idea that the content of "municipal affairs" is indefinite in its essentials is one that has taken root in our cases on the subject. We have said that the task of determining whether a given activity is a "municipal affair" or one of statewide concern is an ad hoc inquiry; that "the constitutional concept of municipal affairs is not a fixed or static quantity" (Pac. Tel. & Tel. Co. v. City and County of S.F. (1959) 51 Cal.2d 766, 771, 336 P.2d 514); and that the question "must be answered in light of the facts and circumstances surrounding each case" (In re Hubbard (1964) 62 Cal.2d 119, 128, 41 Cal.Rptr. 393, 396 P.2d 809). "No exact definition of the term 'municipal affairs' can be formulated and the courts have made no attempt to do so, but instead [812 P.2d 925] have indicated that judicial interpretation is necessary to give it meaning in each controverted case." (Butterworth v. Boyd (1938) 12 Cal.2d 140, 147, 82 P.2d 434.) But our decisions have also strived to confine the element of judicial interpretation by hedging it with a decisional procedure intended to bring a measure of certainty to the process, narrowing the scope within which a sometimes mercurial discretion operates.