While I prefer creating a Daily To-Do list to help prevent that overwhelming feeling of being swallowed by tasks, I do carry a small notebook around with me to keep track of ongoing tasks when they pop into my head. Tasks that aren't necessarily important to complete today, but that I would like to complete in the future. Typically the items on my ongoing list are things like "touch up trim in the living room" or "transplant day lilies from back yard to front." When they become necessary or when I have extra time (yeah, right), I'll consult my revolving list and add these tasks to my daily list.
I also use this small notebook to track collective lists of items to pick up at places like the hardware or housewares store. Rather than making a specific trip out to pick up just one item, I wait until I have a few things on my list to save time (unless I really need the item right then.)
This notebook also came in handy while I was pregnant and had a question pop into my head to ask my midwife, item suggested to add to my registry or any thought I wanted to remember (anyone with mommy brain can tell you that the most important thoughts and questions can be there one minute and gone the next.) Having a place to write those thoughts down can be very beneficial in preventing "forgotten thought syndrome."