I seem to go through odd phases with the stationery that I prefer to use. For years, I was all-Moleskine-all-the-time. There was something about that that particular size (13x21cm) that just worked for me.
Then I fell madly in love with the Traveler's Notebook (A5-slim). I'm on my second one now, and I've filled multiple refills.
Then I discovered big notebooks. I used a Leuchtturm1917 Master Slim for a while. Before that, I used a Life Noble in A4. That was a great notebook. It took a beating and still held up. That's the notebook where I wrote out all of our fundraising stuff to prepare for the mission field. Even now, when I do my note-taking for sermon prep, I am using a big(A4+), blank Rhodia tablet.
A size that I never thought I'd find myself using regularly is that of the Traveler's Notebook in passport size. It's a dinky, little thing. I can just about hide the entire page with the palm of my hand. But that diminutive size means that it's easier to grab. It takes up less space in my bag.
I'm nearly done with the first refill after starting it on 1 March. Even for a month where everything fell to pieces because we all got covid, there is a surprising amount that I wrote down. A single spread has enough room to take notes while listening to a sermon if I keep my pencil sharp.
I don't know if it will be a long-term journal, but I'm enjoying it while it's my daily driver.