My Cannondale was designed for long distance multiday touring, but has suffered the indignity of being a winter bike for several years, plus has had many of its touring components swapped out for whatever was handy as they broke. The bike is old enough to take 27-inch wheels rather than 700c, and over the years I've gravitated towards building it up for ease of emergency road maintenance. So, it has a Shimano freewheel (since the tools, and replacement wheels that take them, are more common) instead of a freehub, and Schrader valves, and deep channel rims so that I don't need tire irons, and no sealed bearings, not even in the pedals. Putting extra racks and bottle cages on (I rode with 5 cages), I made sure all of the hardware was 10-32 even where it didn't have to be. Even so, it's a pretty miscellaneous bike with some cheap and/or old parts. It lost its triple gearing and long-cage derailleur a while ago, so the lowest gear I had was 42/28, which was enough but only just. One of its brake levers has an attachment bolt that my multi-tool won't reach, so I brought separate Allen wrenches. I also had a miscellany of nuts on the bike, not all of them metric, and wound up bringing *two* small Crescent wrenches, plus two kinds of oil (both of which we used), spare hardware, some extra spokes that kirkcudbright had left in his panniers, one of those 8-position spoke wrenches, a small Philips screwdriver, and I don't even remember what else.
And sure enough, plenty of things broke or needed adjustment on the ride. Riding up it was limited to losing signal on my bike computer in the rain and adjusting my right cleat to address some knee pain, but on the way down I lost a rack bolt the first day, broke the rear rack and a spoke the second day, and then having fixed that (and relubed the chain) broke a second spoke the third day. At that point it was time for a new wheel, and at the first bike shop we visited I realized that the lowest-common-denominator bike component theory doesn't really hold water. For sure enough, they had exactly the $20 solid-axle steel-rim 27-inch English-threaded rear wheel I expected I'd be stuck with... and I was not confident it would be any sturdier brand new than my falling apart wheel was even without all of its spokes. And while that shop had nothing nicer (and certainly nothing in 700c), there were plenty of better-equipped bike shops and we had no problem just bailing on the lowest-common-denominator shop and heading someplace with a better selection.
Now by "better selection" I don't mean that the wheel I bought was particularly good; the left-side spokes were all kind of loose and the bearings probably need to be adjusted or maybe even repacked as they've dried up, but it was as nice a wheel as the one I was taking off, which I didn't feel at all bad about leaving behind. I started putting the old tire on the new rim and realized that it was 80% worn, so I bought a new one, which saved me some trouble but also didn't help me remember to do anything about rim tape, and so when I tightened all the left spokes the next morning some burrs on those spoke nipples (from where they'd been adjusted with a screwdriver instead of a spoke wrench -- who does that anyway?) tore holes in the tube, and so it was off to Mountain Cycology in Ludlow for ($1.00 rubber!) rim tape, a couple of tubes to replace the one I'd thrown away with the wheel and the one I'd torn up, and a lot of great route advice.
miss_chance, by contrast, bought herself a shiny new Surly Crosscheck, and once she outfitted it with triple gearing, street tires, fenders, and a rack the only issues she had were fit issues. She raised the stem to about 1mm below the top at the beginning of the ride and the rest of the way to the top while we were in Montreal. She also tried a seat cover in Montpelier to reduce friction against the different fabric of her otherwise-identical-to-previous seat before deciding that seat choice depends too much on riding position and replacing the seat entirely. Even her (wireless) bike computer was more reliable than mine. She did lube the cantilever cable on her brakes to make them center more easily, and pick up new gloves with padding in more places now that she had a bike with more hand positions, and about 500 miles into the ride we had to tighten the brake cable to make up for brake pad wear, but really she just had the right bike for this ride instead of something that worked well enough. My Cannondale has some front end issues which I think mean it is nearing the end of its life; when it gets there, I'm tempted to replace it with a Surly as well (though I like a shorter bike front to back, so for me it's more likely to be a Long Haul Trucker than a Crosscheck).