As a general rule, I rarely threw a CH following a CB, or a CB following a CH. However, I did regularly throw back-to-back CHs and back-to-back CBs -- i.e., "doubling up" on those pitches. Lots of pitchers do this.
If I threw a CH, I always liked to go back to the FB (if I wasn't throwing another CH) to lengthen out the arm again -- I felt it made my off-speed more effective. For some reason, and perhaps it was all mental, but I never threw a good CB immediately after a CH without first going back to the FB.