Don’t rely on others. “People need to recognize that now there are different cassette sizes, so there are different chains depending on what gear you have. A lot of people are like, ‘Oh my friend is always prepared they always have the stuff, I’m not going to bring anything.’ All of the stuff now is very bike-specific, and you have to have your own package of stuff.”
These are some great ideas, especially the simple ones like bringing a garbage bag. That’s something so easy and cheap that it’s easy to forget entirely, but as you say, it can make a huge difference in the right circumstances. It’s also good that you discuss some minor bike repairs. That’s another thing that can salvage or destroy your ride. You want to be as prepared as possible for the best possible experience.
I bicycle to and from work to save gas. I don't have a fancy bike, it's just a Schwinn mountain bike that's comfortable and can carry me plus gear but I want to be able to do my own work on it. I needed a book that was simple enough for someone new to bicycle repair and maintenance but could take me through all the upkeep my workhorse needs, and this book does just that. It's well-written and easy to follow.
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.