That still doesn't mean that you should do any of those operations by hand (which is what the previous comment was about). But sure, if you do scheduling for f

That still doesn't mean that you should do any of those operations by hand (which is what the previous comment was about). But sure, if you do scheduling for future times, you do need to be aware of such possibilities and store the future times as civil times (and have some sane way of handling non-existing/repeating times - but again, most of the time the system/library will do this for you). Then even if the user is flying across the world, they can still get the alert at the right time wherever they are (assuming the device updates local timezone based on location). I never said that you should only store absolute times - only that they are a separate data type and you shouldn't mix them or try to convert them by hand.