Unless taking care of it means you've replaced the battery, there's no way it is performing at the same battery life retention which is what he was referring to.
Indeed! The sad thing is, I got this phone because someone was giving it away because it has a "spicy pillow" battery. Samsung fucking glues their batteries into their phones, but I was able to carefully remove it and replace with a lot of work (and a new screen cause it practically shatters when touched).
It was still cheaper than a new phone, but given it's on its second life, this phone is getting on in years. Those batteries basically just become bombs after a few years.