Methods, devices, and systems related to memory device on-die ECC data are described. In an example, a scrub operation can be performed on data in order to determine which rows of memory cells in an array include a particular number of errors. The particular number of errors can be a number of errors that exceed a threshold number of errors. An address of the determined rows with the particular number of errors can be stored in memory cells of the array for later access. The address of the determined rows can be accessed to perform a user-initiated repair operation, a self-repair operation, a refresh operation, and/or to alter timing of access of the cells or alter voltage of the cells.