If you are planning on going on a multi-day ride or just riding a long distance in a day, you should have something for first aid, just in case. Unfortunately, almost everyone who cycles frequently will go down at least once in their life. This kit can be really small and compact and can include bandages, some gauze, and a small bottle of a disinfectant.
It has some useful information for basic repairs... not so heavy on the maintenance side but there is some in there. The pictures and drawings are in black and white, but mostly visible. Only a few are difficult to see. However, they are in 2-dimensions and they don't show you HOW to do the thing, they only show you the general area and the part you want to manipulate. The phrasing in the instructions can be hard to follow without a good visual reference unless you're already a master bike mechanic (which you aren't if you're thinking about buying this). So, buy this for general reference and rely on Youtube for video. The two together are better than either one alone.
More than any other tool in the kit, a reliable lever makes changing a tire easier, especially if you have road bike tires, which are difficult to remove. However, throughout testing, levers seemed to be the one item more prone to failure and poor design than anything else. For example, I found a random orange lever floating around my basement and I threw it in the test pool for fun—it seemed solid enough … until I began prying at the rim of a tire. It bent directly in half, slowly and smoothly, like taffy, and then was boomerang shaped forevermore.
Every expert I spoke to recommended Pedro’s Tire Levers by name. They have a wide body—a different shape than other models we tested—and that prevents breakage, but more important, the broad, flat surface area of the tip helps it stay locked under your tire. When a lever slips from under the bead of the tire, you can end up repeatedly scraping your knuckles on the spokes of the wheel, which is so annoying. Pedro’s levers are small enough to fit into a saddlebag, are sold widely in bike shops, and even come with a lifetime guarantee. If one breaks, Pedro’s will replace it.
Riding the bus with three infants in a stroller is no easy task, especially when you realize you have a flat tire as soon as you step foot on the pavement of 2nd and University. Luckily, I found The Bicycle Repair Shop. Andy happily filled my tire with air, and when it was flat again an hour later, found a replacement tube in minutes. He changed the tire with the babies still in the stroller! This was such an amazing experience that totally made a fun day possible for us! Thank you, Andy!
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.