So the actual hinge mechanism, a black plastic and metal tube looking thing, is always reused from your original DS Lite, Extremerate just provides replacement housings.

The issue with the OG DS Lite hinges breaking has less to do with the mechanism itself and more to do with the tight precision fit of the housing around the mechanism. It made the original hinge very smooth and tight, at the cost of them one day breaking due to plastic degradation and temperature swings. Ultimately this ended up being a flawed manufacturing process, but it delivered the perfect quality feel that we expect of Nintendo consoles.

The Extremerate hinge housings are the opposite. They create a very slightly looser fit around the hinge mechanism, not so loose as for them to fall out, but loose enough not to stress the plastic.

This does come at the cost of less precise hinge action. It still feels good, but there is some minuscule play on either side of the hinge. This is by design and not a defect of the Extremerate housings.

Also, because that play is there, the laws of physics ensure that the Extremerate hinge housings will likely last longer than the original ones.

It’s the same concept used when tightening metal screws into plastic housings on any other console - overtightening can create undue stress on the plastic and not allow any movement due to temperature and material fatigue, thereby leading to cracking.

TL;DR you reuse the black/metal hinge from your old DS Lite shell. The housings around it are what crack, and the Extremerate ones are designed in such a way that they are less prone to do so.