tried to find a picture that shows how small these a8 cards are.

a3 is gigantic already. i've seen a big printer once that can print it. i have one big a3 clipboard and a bit of a3 white paper that i use to make gigantic overviews/flowcharts when i am dealing with something complicated or overwhelming. also i draw maps of countries i want to visit on a3 paper.

a4 is the default document size. that's what my old black and white laser printer was built for. i used to use this for all my time management but i noticed a lot of the page remains empty and i don't end up doing that much. after having used smaller sizes it just feels too unwieldy and currently i don't really use the size for anything.

a5 is about the size of a small regular book you put in your backpack. i buy a5 paper and use a5 for writing to do lists because i noticed i live in poverty and wherever i sit, the tables are small and the tables at my home are either tiny or full with stuff so a5 makes everything easier.

a6 i might use this when i build a piece of furniture and need a small canvas to make sketches and hold measurements.

a7 this is the regular small index card i have been using a lot lately. this feels like a good size to develop an idea over time and have a bit of space for updates

a8 this is the tiny index card size i only bought a few days ago for the first time and put them in the tiger cigarette case. that's just big enough to fit a headline and a sentence of text or two.