Make a habit of writing down your thoughts, not necessarily on “something big and important”, but something as casual as how you are feeling at a particular time, your views on topical issues etc. The good thing it does is that helps you probably in few years time to see your thought process at a particular point in time in your life. Capturing your mind, experiences etc in a permanent form not only makes for easy recollection of certain details, it helps you to conveniently pass down your values or things you consider important to the next generation. We learn a lot about individuals when we read about them or study their lifestyle and we are able to do this because information about such person is in a permanent form.
Do what makes you happy and capture those memories in a permanent form, you may need to remember or relive those experiences sometime in the future.
Writing down your thoughts and plans also helps to make whatever project you want to embark on more real, it moves it from an idea you have to a well executable project. Where such an idea is not executable, writing it down shows you exactly why you need to do a better research. The benefits of putting down your thoughts and experiences cannot be over emphasized, if you have not formed this habit, I think you should consider doing so.
Have a great week!