I tend to take a little notebook or diary with me everywhere I go. I have a collection of them, filled up with writing/drawing that I keep and get out to look back on...it reminds me how much I've grown and changed, and of thoughts and feelings that might otherwise be lost. As well as being helpful on a personal level, they can be very useful for jogging ideas for projects- playful little drawings can easily inspire something that may not come about when approached in a less relaxed way. It's always interesting when other people contribute too. To me, they're pretty essential, and I would recommend it to everyone. That is, if you can get past the potential discomfort in being viewed as massively pretentious sitting with your head buried in a notebook out in public. But most people aren't so judgemental these days!