Never. I tried the RC stuff 10 years ago when I took my first stab at learning to LD. It was useless.
I agree. I have never become lucid by doing an RC. Whenever I become lucid it is always because something makes me suspect that it's a dream, like noticing a personal dreamsign. Then I use RCs to confirm it. On the other hand I think that developing a critical attitude toward reality (i.e., "could this be a dream?") has often helped me become lucid in dreams.

I use WBTB + intention. Any other technique I use is a variation thereof.
Yep, WBTB is a killer technique. According to LaBerge it will increase your chances of becoming lucid tenfold.