One possible problem with running premium is that it usually doesn't sell as fast as regular because of the price, so there's a chance the premium will sit longer in the station tanks. Probably not an issue with the major brands in a busy area, but might be a problem in rural areas or stations in, um, low cost areas in the city.
A brief history of "Change":
Soviet Union - April 3rd, 1922; Italy - April 6th, 1924; Germany - January 30th, 1933
Cuba - January 8th, 1959; Cambodia - April 17th, 1975; Venezuela - December 6th, 1998
United States - January 20th, 2009