If you're heading towards any sort of long-term goal, a simple journal can be a very powerful tool. In it, you can track your progress day by day and week by week. It might not seem like much at first – but pretty quickly, you'll find that you can flip back to previous weeks and see how you've improved.
The very act of recording something often helps you to be motivated to do it, too! This works really well for exercise programs, diets, reading plans, studying...
When I'm feeling upset or anxious, journaling almost always helps. It gives me a space to spill out what I really think, and often seeing it in black and white gives me a sense of perspective!
Many people find that writing about problems is actually more helpful than speaking about them.
One day, your journal could be a very interesting historical document – for you, for your family, and potentially for a wider audience. Obviously, you might not want anyone to ever read the journal itself, but by recording details of your life, you'll have them for future reference.
Your memory will fade over time, and things which seem perfectly normal and commonplace now might be fascinating to your grandchildren. With technology changing especially rapidly, the world of the early 21st century might seem almost unrecognizable in a few decades. A journal can keep these memories alive.
If you keep a journal regularly over a period of time, you're going to become more aware of your own thoughts and feelings – and perhaps your failings. You'll spot patterns, both positive and negative ones.
Few of us take time on a daily or weekly basis to step out of the busy moment-by-moment flow of our lives. But this higher-level reflection can be incredibly important, even life-changing. A few sessions writing in your journal could lead to a breakthrough that gets you to change careers, get fit, or turn your life around.
Finally, keeping a journal will almost certainly help you to become a better writer. This might not be a benefit that you're necessarily looking for – but almost all of us have to write in some context (perhaps emails or reports at work).
Regularly journaling helps you get into the habit of writing, so that it seems like less of a chore. It can also help you to express yourself in different ways through words – perhaps you might write a poem in your journal, or deliberately try to expand your vocabulary.