These aren't for everyone, but if you're anything like us, they're totally for you.
We've had ours forever and we love them - they're our "forever sharpeners". We use them as pencil stands on our desks - one sharp pencil (all one needs), always ready.
But here's the deal: Sometimes kids underestimate their own strength. If you use Hulk-hands to tighten the caps, they'll weaken over time, and crack.
You'd think it was the glass that would break. NOPE, it's the plastic.
That said, we highly recommend them, just not for incredibly strong children.
The glass portion is quite durable - we've never had one break as a result of being knocked off a desk or dropped (knock wood).
These aren't disposable, so they shouldn't really have an "end", but if you break the glass or the plastic, the shards go to landfill and you can reach out to us if you'd like to order a replacement.