The group I travelled to Fiji with was a very safety conscious, conservative bunch, led by a Course Director from an ultra-conservative dive agency.
We did not dive on the day of our arrival. That was a good idea, since we were all tired and dehydrated and hungry for real food from the long 12+ hour flight. We spent the first day eating and sleeping and acclimatizing to the 99% humidity and 99^F heat. Thank goodness for air conditioning in tropical hotel rooms!
We did not dive the last day of our stay either. That was a good idea as well, since there were other activities available near the dive site, like horseback riding and waterslides. Several people spent that whole last day sleeping. I spent it freediving. There are loads of things you can do on the last day that do not need to include scuba. One hillarious couple spent their last day drinking alcoholic mixed drinks, and joking that they had fasted from alcohol long enough, and this was their day to catch back up.
24 hours of no diving before flying seems like a pretty good rule to me. Why play roulette with your body by cutting the time interval?
I believe that if you want to become a happy, old diver, you should practice conservative skills. Ask not, how far can I push the envelope of safety? Ask, how can I be really safe, so that I can live to dive another day.