I've had a couple of second opinions for far less serious stuff in recent years. In both cases the original doctors suggested major surgery pre-emptively, even though they were very different types of thing.

In the first case, I decided to talk to an expert in the particular area who then ordered different tests. These indicated the issue had actually gone away completely, and I avoided surgery as a result of those.

In the other, a grade 2 ACL tear, it was less clear-cut, but I felt like the explanations given by the second doctor as to why he'd recommend against surgery were clearer and made more sense to me.

I'm glad I got both second opinions and the first case in particular, made me much more likely to get second opinions in future as well as more confident about doing so.