There's more than enough things that are obviously, from a fit, finish, design, etc. standpoint simply not built to last. These days, you'll often see them referred do as "cheap plastic crap from China", or something similar. Similarly, the lifespan of clothes washers and similar appliances these days are not what they used to be either, even in the more expensive brands.
Even with more expensive brands where the fit and finish is good, it's usually cutting material amounts to save weight and costs resulting in components that fail after too many repeated stresses within normal operating tolerances (in other words, not abused).
Unfortunately, there's another plague that is harder to spot, but just as annoying and insidious: Things where the design is good, but they cut corners on the materials, killing the lifespan or usability of the machine. Reputedly this is what happened to the mid-80's flight Corvette, which had a reputation for being squeaky and somewhat flexible of body. I no longer remember the source, but had seen a comment that the fundamental design was good, but the GM beancounters, in an effort to shave a few bucks off, used lower grade alloys than specced - which would have been stronger, etc., and resulted in less flexing of the body, and so on.
I can't speak to the truth of that. Here's what I can speak of.
A number of years back, needing a new vacuum because the old, light stand-up bag vacuum was unrepairably dying, and gaining a canine of the shedding persuasion, we looked at options that had grooming attachments and were built with shedding pets in mind. The final choice came down to two vacuums. A Shark, and a more expensive Dyson D65 "Animal". After digging through the reviews, reliability notes, manuals, etc., I ended up settling on the Dyson.
Sure, it was heavier than the old standup - both were - but it had the following advantages over the Shark:
- Everything that needed to be cleaned and checked could be quickly and easily removed and cleared out without tools. This especially included the main powered brush head, which had been a particular sore spot with the old one.
- The same powered brush head had a very low profile of it's wings, so that in conjunction with the maneuverability of the base "ball" allowed me to get under edges my previous vacuum or the shark couldn't.
- The pet grooming brush attachment works like a champ.
- The small upholstery/furniture/stair head has a great design that can suck up long threads without tangling.
FWIW, demonstrating that the fundamental design insofar as shape is solid, all of these still work great, as designed.
No, the issue goes back to what I alluded to about materials.
Leaving aside that, with the weight of the main motor assembly the vertical support should be made of a stiffer and stronger material, I've had three parts break on the damn thing due to repetitive stress fractures.
You know how IKEA tests all of their cabinets through mechanical repetitive tests so that cabinet doors/etc., can be used for a lifetime without falling apart from normal daily use? They even have pretty displays showing that to you?
Part the first - canister inner latch. In the event enough hair gets caught in the canister that the clumped dog hair won't leave past the bottom of the inner assembly, you can push in a gray tab, a button roughly 1/2 inch, spring loaded, to unlock the upper cyclone assembly from the clear plastic shell. It's beveled so that it recesses as you slide it back in place, and pops out at the appropriate hole in the canister to lock the top assembly in place.
That oval plate literally snapped in half, due to the repeated pressure of being depressed as it slid into place as designed.
OK, got that replaced under warranty.
Similarly, also on the canister, where the plastic handle latches in place that opens to remove the upper filter? Part of that separated due to repetitive stress. Not a showstopper, but in light of the third next item, becomes "enemy action", or at minimum, a systemic problem.
There's an ingenious mechanism where the main motor switches between the hose and power head. There's a flexible hose that runs from where the power head connects to the collar for the coupling mechanism. On the end of this flexible hose is a matching collar, with two ridges for idiot-proof alignment, and a plastic tab with a retainer screw to keep it locked in place as the flexible hose adjusts for when the angle between the handle and power head changes.
The plastic tab broke between the main collar and the retainer screw, resulting in no suction at all when in power-head mode because the hose effectively fell off, out of the assembly.
It's a shame, because the overall design, with better and stronger materials, is solid, effective, and has never given me other hiccups. It's easy to dump, easy to swap attachments, and if you keep the filters clean, has maintained an excellent suction for five years.
All of this, including a reputation for reliability at the time I purchased it, was sacrificed because someone wanted to use cheap plastics where a better quality one, or something other than plastic, was called for.