I think that the timer for sending flasks should be changed from 24 hours to 23 hours. Let's say that I like to give flasks when I wake up at 6:00. For some reason, I am late one day and give flasks at 8:30. If flasks were on a 23 hour timer I could give my flasks the next day at 7:30, the day after that 6:30, and the day after that at 6:00. I would be able to return to my normal schedule without missing a day.
On a 24 hour timer I need to give flasks at 8:30 every day thereafter or skip a day entirely. If I'm late again, then I need to give flasks at an even later time. With the 24 hour timer, players gradually have to give flasks later and later until they are forced to skip a day.
The 23 hour timer is just superior for people on a schedule.