We all know that content types are inheritable assuming that the features of a content type is also inheritable. In most cases this is true, for site columns and workflow. Where it doesn't work is when it comes to Information Management Policies. IMP's are set for the content type and any content type that inherits from it. When trying to change the IMP for a child content type or a document library that is using that content type you get a warning that states that you are unable to modify the IMP and if you want to change it you will have to do it at the parent content type.