Understanding how values interact is fundamental to planning the conservation and use of natural resources. However, practitioners who apply value classifications use a diversity of approaches. Does this matter? In answering this question, we propose that well-constructed classifications contribute to planning by: clarifying definitions and underlying concepts; providing a basis for assessing synergies and trade-offs; explaining some ethical constraints, including aspects of governance and power; and providing a framework for cross-cultural analysis. To test these propositions we develop complementary value classifications for end state values and principles together with supporting theory, assumptions, and criteria. The proposed classifications are then compared with alternatives including those based on ‘needs’, ‘capabilities’, and total economic value. We find that the alternatives fail against key criteria and this hampers their capacity to fulfil the four roles proposed above. Therefore, we conclude that although value classifications are important and may vary depending on purpose, they need to be well-constructed – that is, supporting theory, assumptions, and criteria should be explicit.