I use my sketch journals for many things: lists, reminders, travel log, idea generator, storytelling, and, of course, sketching. Originally I purchased ready-made blank books, but now I make my own. This way I can choose exactly the size I want and fill it with any paper I like. And it's not always the same paper from cover to cover. I might mix heavy watercolour paper with a few sheets of toned paper here and there, and some with thinner paper, more suited to writing or pen drawing. Whatever I do, it's always nice to hold it in my hands and know that it was completely my creation.