Oh! I thought of the other main thing I wanted to say in my last post! Better late than never, right?
Another aspect of the leave time vs. arriving time is going to bed (and this is flylady's idea). Instead of saying to myself "be in bed by 11:00." I tell myself, "start getting ready for bed by 10:30." That way if I am sleepy, I go through my before bed routine fast and am asleep soon. But, if I am not sleepy, I am still on my way to bed but am able to spend more time reading without feeling guilty and without a computer screen in my face stopping me from feeling the "sleepies."
As a result, I have been blessed because I never lie awake in bed unable to sleep. If it takes me more than 3 minutes to fall asleep after I turn out the light then I consider that a long time to go to sleep!