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.

We focused on tools that would be useful to a commuter—someone trying to use a bike as a functional way to get around town, as opposed to riding recreationally (road biking and mountain biking). That said, it’s a wild and wooly bicycling world out there, and the streets are packed with so many different bikes, all shapes and sizes, new and old. Customizing your flat-fixing kit has advantages over buying a preassembled kit that always contains a tool (or two or three) that’s a piece of junk, or you don’t need. Or it’s missing something you do need. If you build your own kit, at least you know everything works. And you can add only what’s necessary for your specific bike without ending up with stuff you don’t need.
Otherwise, this tool should serve the average commuter well. Specifically, we think you’ll find the size 4, 5, and 6 hex keys, extremely common sizes in bicycles, very helpful. They’ll adjust seat-post heights or let you remove the saddle entirely, or tighten a loose stem that’s always rattling apart. The Phillips head will tighten loose bolts on shoe cleats or the rear derailleur. The most common use for the torx would be adjusting disc brakes if you have ’em.
If you’re going to use the chain whip you just made, you’ll also need a way to get that cassette off. A lockring remover is a must-have; unless you use one of the shady removal methods I’ve seen on the internet—which I wouldn’t necessarily recommend unless you don’t care much about the condition of the wheel after you use them. I recommend Park Tool’s iterations here that cost about $6, but you’ll need to buy the specific one for your brand/type of cassette. (By the way, I’m assuming you already have an adjustable wrench laying around somewhere to use with this tool. If you don’t, well, you’ll need one of those too.)
It is a good solid stand made mostly from heavy metal, but it does have a couple of problems. (I will use part names from the instructions to explain.) First, the clamp between the "telescopic bar" and the "upright" is plastic. It arrived broken in the box. Whoever boxed it should understand that if you put it in the box broken, the customer will remove it from the box broken. I did not return it as broken because I was able to Gorilla Glue it back together and it works fine; it clamps tight enough to hold the telescopic bar in place. Second, the "bike support stand" (the horizontal bar at the top that holds the bike), when attached to the seat support does not grip tight enough to hold the bike in the position I set because there is too much weight from the front of the bike. The torque causes the bike to rotate until the front wheel is on the ground. That is not enough for me to return the stand because I seldom work on the front wheel and if I do I can attach the stand to the top horizontal of the bike frame. I think they could fix the problem by not making the "bike support stand" so smooth, give that part a sandpaper like finish or put rubber fingers inside the clamp so the part does not slip under the torque from the weight of the front of the bike. I might rough up the stand part with sandpaper, or put small grooves in it to give the clamp something to grip on to see if that solves the problem. Third, the clamp holding the bike frame even at full tight will not keep the bike from rotating around the frame. It is not enough for me to send the stand back, just a minor annoyance. The problem is there is smooth plastic trying to clamp a smooth metal frame. I think they could fix this by putting thin rubber pads in the clamp. I will probably run out and get some pads to try that out. I think it is a good stand for the price. The stand itself is made from much heavier metal than I expected. It is very stable with the four legs. I easily overcame all the issues so I kept it.
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.

Friction gear systems are a lot simpler to adjust, because the movement of the derailer cable can be modulated as you ride, every time you change the gear- they require less cycle maintenance. Modern index shifting systems are a little more complicated because each ‘click’ must release the exact right amount of cable to allow the derailer to move the correct distance to move the chain from one gear to another. Setting up and adjusting a derailer is not difficult and requires only basic tools, but there is a methodical procedure to follow.