Luggage shopping starts with the wrong line on the spec sheet. Every hardshell box says polycarbonate, including bags molded from blends that behave closer to ABS, so the material word separates almost nothing: two shells both stamped 100% polycarbonate can differ more in real toughness than polycarbonate differs from ABS, because the three variables that govern shell behavior, thickness, resin grade, and molding quality, are printed by nobody. The durablepicks carry-on teardown prices bags the way a mechanic would: by the order the parts die. Wheels and zippers fail first, handles next, the shell last, so a dollar is only earned when it moves a failure date, and anything that merely changes how the bag photographs is polish.

The first jump up the ladder is the only one that buys measurable engineering. Budget bags run spinner wheels on sleeve bearings, a pin riding in a plain sleeve that collects grit, develops play, and starts dragging within a few hard years, while the mid tier seals ball bearings against grit so they outlast sleeves by years. The zipper chain steps up from a small coil that splits under overpacking to a heavier chain with a machined slider, and the housings step from riveted to screw-attached, which is the whole repairability argument in one fastener. Eight small wheels turning thousands of fast revolutions per trip make bearings the highest-frequency failure on the bag, so the difference compounds. Price it per year served: a $150 bag whose riveted wheel dies at year three and dooms the shell costs $50 a year, while a $290 bag with bolted cartridges that swaps a dead wheel for a ten-minute fix at the cost of lunch and serves twelve runs about $24. The store test takes five seconds: spin a wheel and count the coast, long and quiet means rolling elements, short and gritty means a sleeve. That is what the failure-order teardown of a polycarbonate carry-on on durablepicks.com grades as the one jump almost every traveler should make.

Past the mid tier the engineering curve flattens and the service curve keeps climbing, which is why the top of the ladder is a different product. A $300-to-$450 band pays roughly half for hardware and half for design, colors, and retail polish. Past $600 you are buying warranty depth, and the fine print decides everything, because limited lifetime is a marketing phrase with no standard definition: some policies exclude airline damage, normal wear, and abuse, which is most of the damage a bag ever takes, while the strongest any-cause repair promises cover airline handling for as long as you own the bag through a network that still stocks parts a decade out. That converts the two most common terminal failures, a crushed corner and a torn wheel housing, into scheduled repairs, which is real money for a frequent flyer and little to anyone else. Past $1000 the teardown's verdict is blunter: mostly margin, some service, on shells and wheels that fail in the same order as everyone else's.

None of this needs brand loyalty, because a bag announces its lifespan through its hardware before the shell enters the conversation. Spin each wheel and count the coast. Wiggle each wheel side to side, since play in a new housing means wobble and drag within a few years. Look for screws at the housings, the cheapest life extension in luggage. Run the zipper the full track both ways and pinch the coil: heavier elements and a machined metal slider mark the chain class that survives overpacking, while no zipper upgrade buys security, because a coil chain opens to a ballpoint pen either way and a strap over the pulls does more than any premium brand. Press both shell faces for symmetric flex and quiet joins, then lock every handle detent and shake, because a day-one rattle is a fastener problem that only grows. Finally find the warranty's exclusion sentence and check whether airline damage is covered and repaired through a real network. Spend to the low $300s on sealed bearings, a heavy chain, and screw-on everything, confirm the exclusions match the travel you actually do, and the checklist in the sixty-second luggage checks on durablepicks.com makes the word on the box the least interesting thing about the bag for the next twenty years.