I can only speak from personal experience.
So, why do people buy shredders? Do they think; I'm an adult now, "striking out on my own", "fleeing the nest", etc, etc, so I'll do all the responsible things, one of which is getting a shredder so I can be a proper adult and shred all my important stuff as soon as I get them?
Or do they, as in my case (and likely 99% of evey other human's cases) move into their new home and then 18 months later realise they have an absolute mountain of sensitive personal info, go out and purchase a fifteen quid shredder and plan an evening of destroying 300 pieces of paper only to find that their shiny new cheap af shredder stops working after a few minutes? They then chuck it (because 15 quid is less than the price of a round of drinks) or intend to but just hoy it in a room they never go into! I should really post a out of the room that my shredder had been languishing in the past 18 months!
It's stopped working because it's pre-set to to do that is my guess. And yeah, respect to Tortoise who has posted facts that make this discussion essentially redundant, but hell, what's the point in life without a bit of pointless discussion? I'm sure that sooner or later (probably later, tbf) the status of a shredder will be critical to a major crime so at least it will be referencable here!