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.”
Next, two-stage designs. There are two types of hand pump. HV (high-volume) pumps, ones that pump a lot of air but don’t have a lot of pressure, which are used for mountain bikes. The Lezyne Alloy Drive is a high-volume pump. Then there are HP (high-pressure) pumps, which pump a small amount of air but can inflate to very high pressures and are used on road bikes. Our top pick is a high-pressure pump.
Be organized. “I like having everything be really small and super organized. I put all of my tools in CamelBak’s Tool Roll. It’s got little compartments, and I can separate tire changing stuff in one place, stuff like extra pedal cleats or an extra derailleur hanger in another, and it all rolls up into this tidy pouch. If I do have a repair, I can pull that one thing out and lay it out on the ground and it’s easy to work.”
A pair of disposable latex gloves:  Not absolutely necessary, but good for keeping grease and grime off your hands during a repair.  Also, nice to have in an emergency when it starts raining and the temperature drops 20 degrees and you don’t have a pair of regular gloves.   Just keeping your hands dry and the wind from directly blowing on them makes a huge difference in comfort.
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.