We have regulators in house now who were surprised we didn't have them in the file. I had told them I thought it could be a fair lending issue and that it just wasn't something that we did, but we document all of the relevant information. Our practices passed muster but did not seem to be an industry standard- we were surprised!
We do keep them all on file for deposit accounts, even though they have a tendancy to get stale in a hurry!