A method for controlling a wind turbine is provided. The wind turbine is a turbine of the type that is operated to perform a control function that controls the amount of power produced based upon measures of fatigue life consumption of one or more turbine components. The method comprises initialising the control function by: over-riding or bypassing (405) the control function for a predetermined period of time, such that power produced by the wind turbine is not altered based upon the determined measures of fatigue life consumption; during the predetermined period of time, operating (407) one or more fatigue lifetime usage estimation algorithms, to determine a measure of the fatigue life consumed by each of the one or more turbine components; and after the predetermined period of time has elapsed, activating (409) the control function and using, in the control function, at least one of the measures of fatigue life consumption determined during the predetermined period of time. A corresponding wind turbine controller and wind power plant controller are also provided.