alan_m wrote:
I've found the opposite with two phones and one camera. Replacement
batteries (always described as genuine) have failed within 3 months.

My experience is that if a battery is called "genuine", you have
to check very carefully to see that it is also described as
"new"/"unused" (which it is probably not).

Batteries from another (random) supplier have since lasted well,
so far.

Same here. I think I get better odds of a good outcome by buying
a random supplier's "matching" battery, than of getting an actual
unused genuine one. Also, if the device is really old, it seems
to me that any actual unused genuine battery may have suffered
from aging.

#Paul