Modularity also comes into play with parts.
Example: Bosch BGS5FMLY2 Relaxx`x … yes, really, I kid you not …
(See, no Typos .)
For what it’s worth this thing is very good (won some test), but after quite a while it loses suction power noticeably and it wants to clean (= rattle) itself all the time to no avail.
The fault lies with a filter assembly, in which over time dust accumulates and prevents air flow, and neither self-cleaning runs of the device nor you as a user have a chance get all the stuff out (I tried).
As you would have guessed, this whole filter assembly is being sold as a spare part (Part no. 708278) and gets rave reviews in webshops, because throwing away the clogged assembly and putting in the new unclogged one solves the problem, hurray!
But sure enough, if you apply some logic (stubbornness will work, too) and really take a look, you can take this assembly apart without a problem by twisting the individual parts against each other … which then enables you to get rid of all the accumulated dust and have the filter assembly and thus suction power back as if brand new.
Of course the user manual doesn’t show that you can do this. But voilà …
(Even has a part no. … 656669
Edit: I just notice that while Bosch confirms this as the part in my device, it looks different - see assembly picture above. Did they perhaps redesign this to prevent the problem? I’ll not find out until my existing part breaks, I’m afraid.)
(Probably part no. 12017969 / 12027830, but I have no confirmation of compatibility, as this officially is not a “part” of this particular vacuum cleaner, even if an explosion sketch at Bosch shows this, it just doesn’t have an individual number to confirm in this particular vacuum cleaner, the whole filter assembly does.)
So, the device is good. It can be taken apart into parts in a meaningful way, too, Bosch even has explosion sketches of it online at its spare parts site.
But at some point along the way somebody decided to apply this dark pattern nonsense of just pretending unmodularity of a part to have customers hopefully shell out a lot of money and throw away perfectly fine parts for something easily fixable without cost and unnecessary waste.
Edit: And in case you want to or have to buy, of course the assembly costs a lot more than the sum for the 2 individual parts of which it (presumably) consists.