Yes, that's a good point about the wastage too. I actually water less than any container can absorb (my handy squirt bottle has a pretty even flow rate) during any pass until the final one. Which is to say I go slow and then stop watering when I see flow through, or maybe flush a bit more for good luck. Pretty much the minimum wastage.
To the extent you can hear air being slurped out of certain containers, I can often hear a little snap crackle and pop in there on the second and third rounds of watering, when they're absorbing the water the fastest. There's a certain sound when the soil is actively slurping, and that provides a great independent confirmation of what's going on underground.
The auditory experience is much more intense when it's hot and dry.
