1 Adam: I didn't print an owner's manual, but I open-sourced the sub design and put it on GitHub. We can access it using our phones.
2 Adam: Then we'll have enough information to work out how to survive being stuck here on the bottom of the Loch! Hopefully.
3 Jamie: But you built the sub yourself. You can just tell us what we need to know.
4 Adam: Why would I bother remembering it once I've written it down?!

This is pretty much why I write things down.

I'll also note that "writing things down" now includes typing stuff into a computer and saving it somewhere.