A major misconception for international travelers is that baggage policies are uniform throughout jurisdictions. This is not the case, as individual airlines have different policies. Airlines also have specific policies: some measure by weight, some are strict on the number of bags and some airlines focus on per-person versus per-family rules.
When booking international travel, research the policies of the particular airlines on which you will be traveling. An important consideration is if you will fly from point A to point B on the same carrier or if you will use local and regional carriers on your journey. Ensure your baggage meets the requirements of the carriers throughout the entire trip. If packing light is not an option, consider using cargo. Cargo is a pay-by-weight service.
Remember that there are various kinds of baggage including carry-on, checked baggage and cargo. Policies vary depending on the area in which your bags shall be placed. (In some regions, carry-on may not be available depending on the size of the plane.)