Some years ago, I used to live on my bike. Riding around daily through any weather condition was bound to quickly wear down on the bike over time. I like some of the stuff that you have in your toolkit. I would say zip ties are actually really convenient, because when something came loose you could go ahead and use those to fasten them down to keep on moving ahead until you had enough time to fix it or get it checked at a bike repair shop.
On the other hand, an on-bike repair kit will be a much smarter selection of tools that you are most likely to need. You should figure out the type of screws that are fitted on your bike and the things that are most likely to go wrong on a ride. Address only these things so as not to burden yourself too much with unnecessary stuff. Moreover, there are bike repair kits used on long rides and those used on shorter rides. The longer the ride, the more tools, and spare parts you will have to bring unless you want to have a very long hike back home.
First, carbon. You already know you don’t need it for your casual weekend pursuits, because you’re not counting ounces the way a professional road racer would. But to quote an article from Velonews, “Remember that professional athletes operate in an entirely different environment than the rest of us. They are all very close to each other in terms of fitness, and they are also all very close to being the absolute best a human being can be. In short, you’re much better off upgrading your legs and dropping body fat through proper training and diet.”
Mini Pump: This actually goes on the frame of your bike, as it’s a bit too big for most under-seat bags. Coming soon, we’ll have a review from Bill of his very favorite one, but a good pump is a lifesaver. Some people instead carry a CO2 inflator, which is faster and easier to use but does require disposable cartridges, and each time you have a flat, you’ll need at least 2 of those cartridges. There are combined pump/inflator tools that we’ll also talk about soon.
Modern bottom brackets use a sealed bearing type construction that keeps water and debris locked out, so they seldom go wrong. Maintenance is impossible so they need replacing when they do wear out. Older style cup bottom brackets need to be re-greased every now and again, and occasionally will need to have their bearings replaced. There are a lot more teeth on the chainring cogs than those on the rear cassette, so need changing less regularly. Cranks usually a solid one piece construction so there is not much to go wrong.