Have you noticed any battery degradation on your product? If so, how long did this take to happen?
After every charge, the next one holds less. It’s a unavoidable consequence of lithium-ion batteries. Usually the average life of a battery is 300-600 cycles. The first few anker models seem to be under this number. I own a first generation power bank from Anker that holds enough charge to charge my phone up around 4%.