There was a bit of debate re this
here.
I think the biggest two issues with this are that it insists on having a time at all, and that if you come to edit it it forces you to re-set the time! If I've already set it to 23.59 it should stay at 23.59, unless
I decide different, not OF!
BTW, there you have one, possibly the best, argument for having one minute increments - setting due to 23.59 is the only way to tell it you don't care what time it's due, only the date.
Mark