I have tested lots of USB and lightning cables but most of them die a quick and horrible death from the extreme pressures of travel. Most end up broken, cracked or otherwise unusable. 

That's until I discovered the wonderful Chargekey from Nomad. 

I wrote a review about it (link) that I encourage everyone to go read. In summary it is a durable, flexible, keychain attacheable USB or lightning cable that goes everywhere with you. 

I have tested other ChargeKey clones from Amazon, DHGate, DealExtreme and AliExpress but none of them are build as solid as the original ChargeKey. For an Everyday Carry (EDC) USB or lightning cable, the ChargeKey gets a 5 out of 5 from me.