Ideally, you're meant to write all three pages off of the morning to clear your head. In this time you can prioritize your day, write about things that are troubling you, or simply how much you'd rather sleep than be awake. Whatever it may be, write it down. I decided to toy with this. In the beginning I wrote in the morning while I had a cup of coffee. I found I was far more productive the rest of the day when doing this. Then I moved on to mid-day writing. I would fit it in whenever I found an opportunity. This lead to a lot of interruptions. Being asked "what are you writing?" constantly can become quite bothersome, but it wasn't that bad. There were a few occasions where I was really grateful I had my notebook with me just so I could work out how I feeling on paper. In those instances, I really benefited from it. Finally, towards the end of this month I tried writing at night. This was useless. I almost forgot to write every day. I would suddenly remember right before bed and would end up with three pages containing variations of "I am tired and I want to sleep. How much do I left have to write?" Even if you can't find time in the morning, do not put it off until the evening. It won't be nearly as beneficial.
Since I began, I have noticed a difference in myself. I feel like things have being weighing on me a lot less. Stress has been easier to cope with and as a result, I've been more positive. I'm someone who needs to talk about my issues, otherwise I get too inside my own head. I've felt less of a need to "dump" things onto others because I'm able to work through it by myself a bit easier. I still talk to friends about problems if need be, it's just not as often now. Even more minor things have been bothering me less. I've been writing poetry more often as well. I really can't recommend this enough. I'd suggest committing to it every morning for a full week to start. I know I'll be keeping up with it for quite some time to come.