I started out following the advice of the everything-but-the-kitchen-sink guys. Ten years and 50,000 miles later, I've cleaned out the stuff I've never used.
Each bike has its own Road Morph G pump mounted on the seat tube. Standard load in all my seat bags is one tube, one tire lever, and a single 5mm allen wrench, since I use 5mm bolt-on skewers. I've never used any of the other stuff typically recommended. Since I keep up with regular maintenance at home, there's no need to carry a full toolkit and spare parts every day...
Interesting, I'm surprised you don't include a patch kit. I guess 99% of the time you don't get a flat, and 99% of the times you do get a flat, it's only one flat, and your spare tube gets you home where you can patch. So it's worth it to not carry a patch kit. For a
teeny extra weight/space penalty, you could get a little pack of those 'glueless patches', which are really just stickers. Maybe someday you'll get a second flat, and that could get you home.
In my
kittier, I carry my seatbag (I don't like my seatbag on my seat, it swings around and bumps my thighs), my Park 3-way 4-5-6 wrench, a bungee net in case I want to hold anything larger on the rack, a faux leather case for my flip phone (which is rarely turned on) and spare 18630 headlight battery. Daily fresh clothes (shirt, socks, underwear -- jeans&towel live at work and get brought home occasionally for washing. shoes live at work). Cable lock and badge for work. It only gets full/heavy if I am bringing food to work. Canned soups/tuna, loaf of bread,...
The seatbag contains a tube, a patch kit, a spare quicklink, a set of allen keys, and a Nashbar Woody multitool. The bike has a frame pump (vintage silca impero with campy head).
In 'rainy season' I'll also carry a folded up poncho, rain paints, and a small plastic container holding half a dozen plastic shopping bags (emergency rain protection for feet and leather saddle).