I recently attempted vibrate mode again, and forget it. It really does eat battery life. I used my phone extremely moderately yesterday, had it on vibrate and only had one reminder. I was down to 54% this morning which never happens when vibrate is disabled even when I use my phone more. I have one mid-day reminder which is non work related and I never get to it on time because I'm not always looking at my phone. I can't have my phone turned on at work. It's ridiculous that one of the recommendations to preserve battery life is to disable vibrate which is a fundamentally helpful function that adds genuinely to the utility of a phone. I never had this issue before 4 and 4S. Does anyone else have this issue or any suggestions?