I've been reading and responding to the forum at Velocipede lately, largely so I can reasonably make use of their classified section with out being a complete douchebag, which I suppose makes me something of a douchebag. Well, someone posting there asked about putting a 130mm axle rear wheel in an old winter beater bike spaced at 126mm. A frame builder and others replied with comments regarding frame alignment, H-tools, and maybe something about a duck (I'm not sure), but this douchebag jumped in with the following point: "winter beater."
Bikes can be detailed, precise machines, but another of their graces is that they don't have to be. If you eyeball the valve lash on an internal combustion engine it will produce awful noises--for a only very short while--but I've enjoyed fantastic shifting for years on bikes with eyeball-straightened rear derailleur hangers. So much can be awful and wrong with a bike and it will still serve the purpose of propelling you faster than you can walk, maybe even in greater comfort.
Case in point: my commuter, errand, rack, general transportation bike. It was rescued some years back from the metal heap at a town dump. Flat tires, seized chainring bolts, missing cables, and all, it made the five mile trip home along side me while I pedaled my other bike and held on to the orphan's stem. Sure, it needed some work, but with mostly salvaged parts I had a nifty new bike with a stiff made in the USA frame that didn't flex much even with a heavily loaded rack.
The years passed, and so did the miles. Things wear, and wear, and then wear some more, but it is a bike and still faster than walking. With likely over 10,000 miles on the drivetrain, I decided to finally put on some less worn parts, not so much because it no longer worked, but more because I have a pile of scrap aluminum that the spiky chainring needed to join. Along with the ring, the brake pads, chain, and cogset (although, I was able to reuse the 11 cog on account of my 140 pound weakling status) were finally put to rest. I took particular amusement from the chain with its loose rollers and generous lateral play.