Unlike many other countries, where the nuclear power plants have a finite period of time foreseen in their operating licence, the authorization in Belgium is delivered without time limitation but on condition of a safety reassessment process at definite intervals of ten years. Important repairs, replacements and modifications (steam generator replacement, seismic re-evaluation and requalification, RCS overpressure protection and process computers) are mainly associated with these 10-year reviews. Beyond those major changes, the follow-up of equipment is performed on a case-by-case basis. Specific monitoring programmes have been developed for sensible equipment to cope with new loading or degrading phenomena (erosion-corrosion, intergranular attack, stress corrosion, wear, stratification, etc.). The lifetime policy is assessed on a pragmatic case-by-case basis; owing to the variety of plants and circumstances, 'generic 'solutions are not often applicable. This Belgian approach is put into perspective by contrasting it to a variety of possible nuclear power plant life definitions.