A status assessment provides an indication of whether and when it is time to repair or replace transformers, switchgear or other equipment.
The useful life of essential main components is assumed to be long, even though it is rarely possible to gain more than a vague idea of how long this actually can or should be. This may inadvertently lead to over-ambitious maintenance routines or situations where longer-term planning is neglected in order to react to current problems.
Long-term planning should include issues such as the overall efficiency of the equipment, in both technical and financial terms, but also (in Sweden, at least) in terms of the working environment in accordance with Section C ("Care of High Voltage Installations") of the ordinance on maintenance regulations issued by the Swedish National Electrical Safety Board (Elsäkerhetsverket).
Status assessments result in the rating of components in a plant with regard to the risk they represent and the consequences of a possible fault. For this reason, concepts such as availability (expressed as a percentage of time required) are also factored into the status assessment.