On documentary shoots one might be out in the field days at a time, in all conditions. And the cameras, and lenses, took a bashing. Using a collimator is not so difficult - doing something to correct misalignments was more tricky.

BTW - if you have interchangeable lenses, the very best and finest grease to lubricate the sleeves of lens mounts can be found be rubbing your finger by the side of your nose where the nostril touches the cheek. ;-)

You can't be me, I'm taken