What do you notice you're forgetting to document?

I spent this evening flipping through old site notebooks, the ones from the 1920s with tiny handwriting and no photographs. They recorded everything but you can tell they didn't know what later people would need. These days I photograph every wall and sherd, but I catch myself relying on the camera and losing the feel of the place. Do you ever catch yourself not writing things down because you assume the record will keep itself?