I'm still doing this after starting a year ago. I've filled up one large ruled Moleskine and am 50 pages into the second one. I have calendar pages where I don't do any forward planning, but just write a one-line summary of what I worked on that day. Empty lines or variants of "slacking off" are an instant sign of trouble.

Other than that, the nice thing is just that I have a designated single nice journal to do any sort of brainstorming notes I need. Random ideas, planning an ongoing project or reading notes all just start by labeling a new page on the journal and writing down whatever is relevant.