(a) Service: When Required. Except as otherwise provided in these Rules, or unless the court on motion with or without notice or of its own initiative otherwise orders, every order required by its terms to be served, every pleading subsequent to the original complaint, every paper relating to discovery required to be served upon a party, every written motion other than one which may be heard ex parte, and every written notice, notice of change of attorney, appearance, demand, brief or memorandum