The stuff I carry with me every day has increased recently (go minimalism!), but what I achieve and enjoy daily has also changed, thanks largely to changing the way I carry my crap around. Where I used to carry just the minimum of things that I would need for my day I am now able to carry a few more of the things that I want. I always put quite a bit of thought into making sure I could keep the number of things I carried as low as possible, such as keeping a set of earphones in my drawer at work so I didn't have to carry any with me to the office. It was carrying my iPad back and forth prompted me to finally give in and buy a bag of some kind, and subsequently broadened my options.
I opted for one of the smallest messenger bags I could find, the Bairn from Trakke. It comfortably holds a 'full-sized' iPad Air, and has no problem at all therefore with my iPad mini (I suspect you could get a 13" MacBook Pro in comfortably, I just don't have one to prove it). I love the plain, waxed cotton, panels of the design. It's waterproof, and it has a minimal number of pockets (only 3 — one of the things I was specifically looking for) and virtually no decoration. I would have opted for something slightly smaller at the time that I made the purchase, but as it turns out it's size has proven pretty much ideal. I'd actually like, at some point, to get the Bairn's middle-brother the Wee Lug, which is large enough to carry my MacBook (15" retina model) when I need to. I'm a huge fan of the Trakke messengers, and haven't seen another messenger bag that quite suits my tastes.
A notebook is something I like to carry around but has often been a bit impractical; so that was immediately no longer a problem. My newer headphones, which are larger (cans rather than buds) and significantly better quality can travel around with me where as before they might never have left the house. Little things like a comb, a pen, a screen cleaning cloth, and my access card for work fit into pockets where I can generally forget about them and still be certain that they are with me. I am no longer reliant on having anything in my jacket pockets, which could be an issue if the weather was good and I forgot to pocket whatever I needed before leaving home. I also now carry my hat around with me, just in case I run afoul of Britain's notoriously changeable and often inclement climate (and if I'm honest I'll happily wear it in any weather, or indoors, or just always).
My immediate memory can be awful; I get distracted and my attention loses track of little things like keys and combs or even coffee mugs (complete with hot coffee). Having homes for these things and building the habit of always replacing them also means that the bag has become practical storage even when I'm not on the move. It's never empty — it's almost a functional piece of furniture. It's now as important to my day as my iPhone.