There's a lot of theories on how to adjust ICs. I personally don't trade them much. I guess it depends on when you'd do the adjusting though. If you are making pre-earnings adjustments, like buying more puts, the risk of course is that you'd be paying top dollar and it would eat into your IC profit. If you think the risk is that great of a downmove out of your range, the best adjustment might be to just close the trade with a small loss.