Mini Pump:   This actually goes on the frame of your bike, as it’s a bit too big for most under-seat bags.   Coming soon, we’ll have a review from Bill of his very favorite one, but a good pump is a lifesaver.    Some people instead carry a CO2 inflator, which is faster and easier to use but does require disposable cartridges, and each time you have a flat, you’ll need at least 2 of those cartridges.  There are combined pump/inflator tools that we’ll also talk about soon.
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.