When doing my PADI open water course, including all the stuff around pressure groups and calculating maximum depth times by hand, I was told that I should always do my deepest dive first, and go shallower in subsequent dives in the day. When doing things with the pressure tables, that seemed to make sense.
Last week, while diving with a computer on a liveaboard, the PADI qualified instructor who was also the dive guide repeated the same thing.
When diving with a computer, does the "do your deepest dive first" rule still apply, and if so why? Or can I just rely on the dive computer to calculate how much time I can safely spend at each depth on each dive, and go to whatever depth on each subsequent dive makes most sense for the conditions?