A wear leveling solution is proposed for use in a storage device based on a flash memory. The flash memory includes a plurality of physical blocks, which are adapted to be erased individually. A corresponding method starts with the step for erasing one of the physical blocks. One of the physical blocks being allocated for storing data is selected; this operation is performed in response to the reaching of a threshold by an indication of a difference between a number of erasures of the erased physical block and a number of erasures of the selected physical block. At least the data of the selected physical block being valid is copied into the erased physical block. The selected physical block is then erased.