Of all the gear in a field or dive bag, cables are usually the first thing to fail - not because they are lower quality than the phone or charger they connect, but because the connector end absorbs constant mechanical stress that a sealed device body never sees.
The failure almost always starts at the strain-relief point, where the cable meets the connector housing. Repeated bending at that exact point - coiling a cable the same way every time, or letting it hang under its own weight off a table edge - fatigues the internal copper strands inside the conductor long before the outer insulation shows any visible damage. By the time a cable looks frayed on the outside, the internal wires have often already been fatigued for a while, which is why a cable can start intermittently cutting out before it looks obviously broken.
Field conditions accelerate this: sand and grit act as an abrasive at the connector seam, UV exposure degrades cheaper PVC jacketing over months of sun exposure, and saltwater residue left to dry on contacts promotes corrosion. Braided nylon jackets resist abrasion better than smooth PVC, and cables with a molded strain-relief boot (rather than a sharp 90-degree edge where cable meets connector) distribute bending stress over a wider area instead of concentrating it at one flex point.
CairoVolt's USB-C cables page lists current options with reinforced strain-relief for exactly this kind of repeated field use.
