JET started initially with metallic walls (Nicrofer 7612LC) and four graphite limiters. Gradually more and more graphite protection has been added and it has now reached 50% wall coverage. The inboard wall was covered with graphite tiles early in JET's operation to protect the wall fram damage and two toroidal belt limiters have been introduced to increase JET's power handling capacity. Carbonisation has been used as an additional tool to achieve certain benefits. Carbonisation has been developed at TEXTOR as a method to simulate for a short time an all carbon machine and as a means to control density and impurity production. This paper reviews the benefits of the extensive use of graphite for protection and limiters and of the deliberate application of thin carbon layers. Attention is given to the changes in the material under plasma exposure, and the damage due to the plasma contact and the machine operation under these conditions. The role of the pararreters of the scrape-off layer in the explanation and prediction of the plasma wall interaction is emphasized.