I write one in the evening and then I specify it and break the tasks down in the morning or whenever I need during the day. It would be difficult to know what exactly I want to do when and how to start which tasks all in the evening, but I do need a general outline of the day so I know what I can spend more time on and do more preparation for and what to directly start. This is just the way it works for me right now, I don't really hold on on a method since I sometimes have just so little tasks that breaking them down is not really needed and sometimes it's so much that I don't even know in the evening what I all need to have done, so it definitely varies, depending on my life situation.
I usually write it at night and then tweak it in the morning. Some things may change and I find that going with the flow saves me a lot of anxiety