Most repairs I can do in my sleep now. But then I open up some ancient fixture nobody makes parts for anymore, or one that a previous guy patched together with whatever he had lying around, and I just stand there staring. The everyday stuff I've got; it's these odd, cobbled-up ones that still beat me.
More people experience this than they realize.
You handle most repairs but the obsolete, cobbled-together ones still stump you.
If this sounds familiar, the Library can help you find the bigger picture.