Back in my undergrad days I took a speach class from a free-spirit kind of fellow who had some pet theories about art and life and the body. One such, which he expounded in vivid terms, was that things emotionally dear to us we keep close to our physical heart: and therefore most men keep their money on their left side: wallets in the back pocket, coins in front. (The heart is slightly left of center in the body.) What do you find in the right front pocket? Dull stuff like combs. Handkerchiefs you find in the right back pocket--the farthest from the heart. Glasses, our tools of vision, are right next to our hearts; because we love seeing the world.
Of course reality was a bit more mundane. I kept stuff classified in different pockets because that's the way my Dad had showed me. I later found it made excellent sense: for every time I reach for my wallet I reach for a handkerchief five times, and I recomb my hair or scratch a scalp itch far more often than I make change. My right hand is my strong/flexible hand, so the tools are best kept handy, on the right.