Abstract: Method and apparatus for ascertaining a at a current time of consideration and for future times of consideration, wherein a first time profile of a base characteristic variable is mapped over the operating time, where the first time profile of the base characteristic variable represents a state of a reference machine at the time of consideration in dependence on the operating time and an actual characteristic variable that varies over the operating time be calculated by means of an individual function, where an input variable fed to the individual function is a performance characteristic variable of the machine, which is detected periodically via a machine data detection unit or is predicted for future operating times, and where the health characteristic variable is displayed as a second time profile by adding the ascertained actual characteristic variable or the predicted actual characteristic variable to the first time profile.