We all have various reasons, but I want to hear yours. A long time ago I started writing a small treatise to reflect on my own reasons and how I developed my own understanding of kendo, as a way/dao and not just a martial art; a practice I have gotten away from and should return to. I encourage everyone to do something similar, write why you practice briefly, and in time return to this thread and see if your views are commensurable with what you thought at the time of penning it.
At any rate, the short answer for me was that is was a means to creating balance in my life or centering myself. When I started kendo I was at a point where I knew my current habits were not sustainable, I was transitioning from post-secondary to a career path, and was in a period of doubt about my self image and who I was. Essentially I was trying to move forward in life without clear direction, and I felt that I needed to find some means to concentrate my efforts, something to anchor myself, a point at which to act as a nucleus for self growth when I felt I had stagnated. I arrived at kendo, my intention was to create an outlet for my physical health, which in turn supported my mental health. It also fostered confidence and decisiveness, something I was lacking. Overall it was a discipline that was both physical and cerebral, I could improve my health and cultivate a more positive mind set, and much more beyond that. Well that is the short of it, so what is your reason for practice?