What indicates that it's time to pot a clone?

Is it the first sign of roots?

Is it when many roots are showing?

Is it after a certain period of time regardless of what they look like?

A poll would be good to see how many people use:

1. Just moistened cubes with a little puddle of water in a propagator

2. Particular accelerator products & frequency with results

3. Straight to a soil filled cup with rooting gel

I'm now eager to find out that ultimate cloning method with 100% success like BUZz UK claims... I'm off to surf Can.com