Index wheels. They're not particularly delicate. They can still be had NOS too.
A few on the bay as we speak.
It was more to do with the what happens when the watch receives a shock that causes the tooth to chip; so not specifically that the wheel itself is delicate. I don't recall the full extent of the explaination as it was just a casual comment on his experiences with them and buying them from semi-reliable sources; the gist being that you don't know if you've got a good'un until it's in your hands.
May have to buy a few of those for the parts box for future use so ta for the heads up.
Also, it's strictly tv dial for me.
That seems the sure-fire way to get my attention.