I value the air in my tanks alot but really dislike having to pay to refill a tank that is 2/3 full.
If your only using 1/3 your air on one dive why not make a second dive before refilling?
Does any ever use just one tank for a trip out?
I do on shallow dives.
"What if" should happen that i end up needing more air.
Than you should have brought 2 tanks, I never have a problem with to much air. I do have a problem with not having enough for me and my buddy if its needed.
How fashionable is it to use a pony on a shallow dive boat,
Fashionable, I don't care about fashion if I did I wouldn't be wearing black.