Creating a To-do List throughout the Week

Tasks that I need to accomplish often pop into my mind in the middle of the day, and one way of freeing my mind of them (and the worry of forgetting about them) is to write them down on a list that I carry with me. I’m thinking about continuing this practice and then using the end result as the beginning of my to-do download for the next week (unless a task needs to be put on my calendar immediately) because if I don’t write them down, I do unfortunately sometimes forget them for another week or two. Can you see any disadvantages to this method? I appreciate your insight!