Method of determining the time interval until a service action is required

Disclosed is a method of determining the remaining time interval until a measurement characteristic of a field device will have drifted outside of a predetermined tolerance range and a service action is required. The method includes predetermining a maximum tolerance of the measurement characteristic correlated/related to the measuring performance of the field device; registering continuously the measurement characteristic of the field device; estimating a lag time interval wherein the estimated lag time interval depends on the drift of the measurement characteristic of the field device in the process specific application; using a method of Artificial Intelligence to determine, at the end of the estimated lag time interval, the remaining time interval until the measurement characteristic of a field device will have drifted outside the predetermined maximum tolerance; and generating a message informing of the remaining time interval until the service action is required.