Is copper-clad aluminum (CCA) okay, or do I need pure copper?

Specialist threads in r/VEDC and r/MechanicAdvice consistently note that pure copper conducts better and is more flexible, but a thick CCA cable in a heavier gauge can outperform a thin pure-copper cable in a smaller gauge. Most mass-market consumer cables, including the ones in this roundup, are CCA, and reviewers generally consider them adequate as long as the gauge is appropriate for the vehicle.