A number of different supplies can be regarded as constituting a single supply. However, in principle, every supply must normally be regarded as being distinct and independent. The differentiation proves difficult in practice. The criteria are ambiguous. Fortunately, the ECJ has made clear statements regarding supplies associated with the letting of immovable property. Utility providers, landlords and tenants should check whether the charging of utilities practiced to date meets the criteria provided by the ECJ. In addition, the ECJ has concretized the principles of its decision in the case of Auto Lease Holland. Companies confronted with problems arising from the Auto Lease Holland case will have more legal certainty. Nevertheless, they should check whether their current practice is in conformity with the new ECJ principles.