In some examples, an electronic device records, in an entry of a time-state data structure that includes a plurality of entries to store respective times, a time in response to invocation of a time-lapse process that lasts a predefined time duration independently of a time clock of the electronic device. The electronic device determines whether times in successive entries of the plurality of entries of the time-state data structure are within a threshold of one another, the threshold based on the predefined time duration. Based on the determining, the electronic device sets a parameter representing a quality of the time clock.