this seems like a good time to go off topic
and brag that my recently-converted-to-8-speed-IGH mountain bike
has not made an unusual sound or missed a shift
in the months since i got it together

this morning
i mentioned my conversion to a co worker who also rides
and he said
I wouldn't care if I never saw another derailleur again
although he rides a full suspension mtb
and so the conversion is not as straightforward an upgrade

all i am trying to say is
derailleurs are a pain in the arse