1. Apparatus for storing data, comprising: an array of bitcells, the array comprising a plurality of rows of bitcells, wherein access to a selected bitcell in the array of bitcells requires assertion of a wordline pulse on a wordline associated with a row in which the selected bitcell is to be found; wordline pulse circuitry configured to generate the wordline pulse; sensor circuitry comprising a calibrated bitcell and a test wordline, wherein the calibrated bitcell is calibrated in a prior calibration process to use, in writing to the calibrated bitcell, a calibrated duration of wordline pulse on the test wordline which matches a longest wordline pulse required by any bitcell in the array of bitcells for a successful write operation to be carried out, wherein the sensor circuitry is configured to signal a wordline pulse duration to the wordline pulse circuitry based on the calibrated duration and wherein the wordline pulse circuitry is configured to generate the wordline pulse with the wordline pulse duration signalled by the sensor circuitry, and wherein the sensor circuitry is configured to adapt the wordline pulse duration in dependence on current local conditions in which the apparatus operates to compensate for influence of the current local conditions on the longest wordline pulse required by any bitcell in the array of bitcells.