Abstract: SUBSTITUTE SPECIFICATION CLEAN COPY A reel device has a reel mandrel for winding up a strip. The reel mandrel has a plurality of segments distributed over the perimeter thereof, which are each joined via at least two link plates to a control rod that can be axially moved in the reel mandrel, for radially extending and retracting the segment. To reliably identify wear conditions of internal components of the reel mandrel that are not visible from the outside, a method for operating the reel device provides that, during the service life of the reel device, the segments are moved multiple times into certain operating positions and in each case the respective distances of the segments in relation to a stationary operating position are determined. The distances recorded at different points in time are evaluated whether they exceed or fall below a predefined threshold value, and wear condition is inferred therefrom.