Not even trying to be edgy here, but I personally wouldn't consider buying a used apple product (that has a battery).

My Mac laptops for work have all failed before the standard 3 year auto-renewal period. Two failed hard drives in the earlier laptops, and 2 failed batteries in the newer laptops. My partner and his family are all iPhone users, and from the observation of a casual yucky outsider (aka Android user), there seems to be a high rate of failure with the batteries. Like, I went the first 10 years of my smartphone existence without even knowing that lithium batteries swell up and die, to now I hear about it on the regular because of Apple products.