Does the sun rise and set as we know it? Indeed, how many suns are there and, if the answer is none, how is light created for your world? Are peoples' lives governed by the clock or do they work according to how many daylight hours there are?
How are children taught to tell the time? Is your world capable of having time oddities where people can literally disappear for a minute or two? Is everyone giving a certain measure of time that is uniquely theirs and what are the implications? (One huge one would be that everyone would know for sure when they would die - how is that handled?).