I am a big proponent of smartphones and keeping your office mobile so you can work when you are not at work. Being mobile, however, does not mean you need to be checking email at 6AM when you get up, or 10PM when you go to sleep.
As this article points out, checking your work email in the morning is never a two minute task. Something will require your attention and before you know it you are running late to work. You are also engaging your mind in work earlier then you need to.
Unless you need to see if a meeting was cancelled, there is no need to check your mail before you get to your office. If something needs a reply, it can happen when you get to the office.
Same thing at night, do not check your work email once you are home unless absolutely necessary. Replying to email after hours will only encourage the recipient to respond. Next thing you know, you just spent an hour of quality family time on something that could have been taken care of tomorrow. Worse, your brain is focused on work when it needs to relax.
Keep yourself sane by tuning out when you are at home.