I did NAUI certification at the university. I struggled a bit with some of the equipment removal/replacement, but I'm fairly proficient at the actual diving and we've never had incidents when we "lost" equipment (though I accidentally dropped my mask in the Atlantic while doing rescue exercises, but it wasn't too difficult to have a buddy pair go down to retrieve it (since it wasn't very deep water). Taping up the mask is not something I've ever heard of being done. When it comes to turning off air, the instructors simply asked us to signal when we feel the air is off, so we know when we are running out and have to reach for our buddy's octopus.
The main problem I've had is when I go down to 30m/100ft and the nitrogen narcosis kicks in. Some people like it, but I hate it.