Broken spokes: memoires of a cycle tourer
The first real pain (after the line of blisters at the seat contact line turned to calluses) was knees:
Get low gears and use them! 80 - 90 revs per minute is required: no, you won't set any land speed records, but you will avoid trouble. And if you can't peddle that fast, then you are using too big of a gear. The first night I slept in a sitting position (night ferry from Shearness to Vlissinden) my knees went out within 20 km of the terminal; it felt like I had a nail driven through each of my kneecaps. It took a week of visiting friends before I could climb stairs without pain. When I slept in my tent, with my legs straight, I had no problem, but it returned after a night on a train. The second time I immediately halted and camped, and was able to proceed after 4 days. There appears to be a connection between these two observations (gears and knees).
Broken spokes: carry spare spokes, check your wheels regularly and replace them as soon as they happen. All I would do was tighten them to what the neighbouring spokes were and start riding; and the wheel would pull back into shape. So you need a spoke key as well.
Oil will not stop the squeeling of the bulls-eye pulley on the rear derailer (which for me started at about 3000 km coming south through the Ardennes). They have to be dismantled and greased.
Front and rear paniers also act as cushions in a side impact. My crank was bent and I was flung sideways, but my legs were uninjured.
Get a cycling cape and leggings as opposed to pants and a jacket. The ventilation is so much better...
I also endorse the Brooks leather saddle...