Cables almost never fail in the middle. They fail in the last two centimetres before the plug, and they fail there for a mechanical reason that is entirely predictable.
What is actually breaking
Inside the cable are stranded copper conductors. At the connector, those conductors are soldered or crimped to fixed contacts, so the cable goes from flexible to rigid at a single point.
Every time the cable bends, that bend concentrates at the transition. The strands flex, and metal that flexes repeatedly fatigues and fractures — one strand at a time.
The symptoms follow in order: charging works only at a certain angle, then it becomes intermittent, then it stops. Data drops out before power does, because the data conductors are thinner.
The insulation splitting is a consequence rather than the cause. The conductors were already failing.
What accelerates it
Charging while using the device. The connector is loaded sideways by your hand, at exactly the point that cannot take it. This is the largest single cause.
Pulling the cable rather than the plug when unplugging.
Sharp bends at the plug — a cable coming out of a socket behind furniture and turning immediately.
Wrapping the cable tightly around the charger, which puts a permanent kink at the transition.
Weight hanging on the plug, such as a phone dangling from a socket.
Heat, which softens insulation and makes the transition point less supported.
The features that resist it
A long, tapered strain relief at the plug. This is the specification that matters most and it is visible in a photograph — a short abrupt collar concentrates the bend, and a long moulded taper distributes it.
Braided nylon sheathing, which resists abrasion and, more usefully, tangles less. Tangling is what produces the sharp bends.
Thicker overall construction, which usually means thicker conductors.
A reinforced or spring-supported neck on cables built for it.
Braiding alone does not save a cable with poor strain relief. The braid protects the middle, and the middle was not the problem.
Habits that add years
Do not use the device while it is charging, or if you must, support the plug rather than letting your hand load it.
Unplug by the connector, every time.
Coil loosely — over and under, in large loops, not wound tight around a brick.
Leave slack at the socket so the cable curves gently rather than turning sharply.
Keep one cable in one place rather than carrying one everywhere. Cables that live plugged in last far longer than cables that travel.
Use a cable of appropriate length so it is not under tension. A cable stretched taut to reach is a cable being pulled at the connector constantly.
Rescuing a failing cable
If it works at a particular angle, the conductors are partly fractured and it will get worse. It is not repairable in any lasting way.
Heat-shrink tubing or tape over a splitting neck supports it and buys weeks. It does not reconnect broken strands.
The one genuine repair is cutting the connector off and fitting a new one, which needs soldering and is only worth doing for an unusual or costly cable.
Buying with this in mind
Look at the neck of the connector in the product photographs before anything else. A long tapered strain relief predicts cable life better than any other visible feature.
Braided sheathing plus a proper strain relief is the combination — a braided cable with reinforced connectors addresses both the abrasion and the bending, and the second matters more.
Buy the right length so nothing is under tension. Choosing length without losing charging speed is covered at SCOVEE Guide.
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