I hardly ever turn my heaps; too much hard work. I have "Dalek" type
bins. I just lift off the bins after about a year or more and leave
the heap to mature, maybe throwing the top, less decayed stuff into
the bin in its new position.
However if I did turn my heap regularly, one of my kitchen knives
would not have been missing so long! After a good clean-up and a rub
on sandpaper for the wooden handle, it is usable again.
So if you are prone to throwing the knife out with the peelings, turn
your heap regularly!

Pam in Bristol