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.
I chose to test these four levers after eliminating everything out there that’s not appropriate for a roadside emergency kit. That includes metal levers. They’re durable, but according to touring cyclist Ramona Marks, “Metal tire levers are trouble. It’s possible to rip your tube even with the plastic ones if you’re not careful, so metal is out of the question, and you don’t want to put pressure against the wheel rim with a metal lever.”
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.