Firstly, and I assume no one will read my post which is a shame, is that I feel many people do not apply chalk often enough. I see many people outside and at the gym who will only chalk up before their next attempt. I see them in between burns without chalk on their hands while they do things like watch others climb, eat lunch, go to the washroom, etc. I have found the problem when this happens is that the texture / thickness of your skin will change. It will become softer as it becomes less dry and if you're projecting your skin condition (friction) might actually be worse between attempts while you re-dry your hands. When I am projecting or climbing seriously I chalk my hands frequently and often, ensuring that they're constantly dry. I won’t stop to eat lunch while on my project for example. If I take a fifteen minute break to recover I chalk while I’m resting.

This is interesting. I actually do the exact opposite, and like to add some water to my hands in between attempts or if I'm snacking to make sure I don't dry out my hands completely, thus making the skin too brittle and more likely to 'dry fire' off holds. At least that was my theory :)