Regardless of whether your car was maintained well or poorly, it is always wise to perform an iron decontamination (along with a mechanical decontamination) as preparation for a wax, sealant, or coating. The reason for this is that if you are going to apply an LSP (last step product) such as one of these mentioned, you don’t want to be sealing in any iron contaminants, which could continue eating through your paint. If you ever plan to apply a protective wax, sealant, or coating, consider doing an iron decontamination with an iron remover.