I send out samples with a report on the track as it came in, and the track as I changed it, and why. So a short sample can be a good idea ... I'd like to have a sample if I was sending out a piece for mastering. These samples can be done in slack time, and are an investment in the time spent. It indicates that I'm bothered to do it, and that I'm the sort of engineer (unknown!) who can be arsed.
From a mastering point of view, there are some jobs I won't do, such as OTT dynamic squashing or a bad case of turd-polishing. Or stuff I can't stand.
Hey, Red Bladder, that was a great sample story. Really funny; I fell off my stool—and spraint my ankle.
PA stuff on FB