it is 1611 if you count transitions of individual digits (i.e.: 8:59 -> 9:00 is three transitions because 3 digits changes) I personally consider it to be 144

it is 1611 if you count transitions of individual digits (i.e.: 8:59 -> 9:00 is three transitions because 3 digits changes) I personally consider it to be 1440 transitions with some transitions involving multiple digits (and hence harder to do) but arguments can be made for both ways of counting.