I am not a rock climber. Instead I use this product to chalk my hands for barbell training. I either workout at home or at the gym. Either place, I don't want a chalky mess. This product is perfect for that and lasts forever. I keep it in a bag, and I never get in trouble at the gym, even though they are strict about no chalk.
The chalk bag is a good/simple way for me to keep my hands dry while playing basketball. First time I tried it for bball, but it does work. Might need to re-apply depending on how much you sweat and you want to keep it in a plastic bag that is resealable.