Like Jumping off a Cliff?

I've always known that there are multiple sources of information that a cataloger must be comfortable with in order to do their job. I use them every day. But reading through a list of them, or even better, trying to re-create my former setup of bookmarks and documentation, makes the whole thing seem quite daunting. Think about it: not only must you internalize the rules of AACRII, you must also internalize the variations that LC has decided upon over the years. Then you have to internalize how MARC functions both within and outside of those rules, and apply the metadata accordingly. And that's just for items that AACRII covers with regularity. Archival cataloging is barely mentioned, rare book cataloging (pre-1801) is literally not dealt with at all, and there are other books for almost all other formats. Don't even get me started on music. Or subject access.
Catalogers are so highly and specially trained, it's a wonder we get anything done at all. I read something once that said it takes, on average, 1.3 hours to catalog something from scratch. ON AVERAGE.
I have a friend who is thinking about applying for a job as a copy cataloger, and the sheer amount of knowledge that is implicit, even in copy cataloging, is pretty terrifying.
And yet, as I look out on this sea of standards for cataloging, and feel myself growing less and less sure of my own abilities in this job, one of the other original catalogers asks me a question today, and prefaces it with "In your vast experience with cataloging multiple formats, have you ever come across THIS before?"
Two things:

1. No. I have not come across this before.
2. Vast experience?

Then I think about it. I DO have vast experience in multiple formats, mostly because I kept getting myself into jobs where people just threw stuff at me and told me to catalog it. Maps, lithographs, books, archival collections, CDs, DVDs, lectures, speeches, photographs, postcards, I've described them all. And not to "date" myself, but I'm only 28. Surely someone here is eventually going to call me out at some point.
And really, I still don't feel comfortable cataloging all the time. Making the leap into using "cataloger's judgment" is scary as hell. Who's to say that I know what I'm doing?

And then I think about the famous words of Dr. Miksa--"God will not smite you if you make a mistake in cataloging." It's comforting, because eventually I think that all catalogers have to get over that fear of leaping. It's just information, after all.