I think in some cases, it's all a person has to work with, and no one else has stepped up. I know for instance, there's a TV movie I want to do, but it's not available on DVD at all and only available on a VHS that's very hard to find. So if I ever get my hands on it, it won't be up to my usual quality and will likely even affect what I can use.

Mine all come from the best copies I can find and I rent a lot from Netflix. Unfortunately, as was the case with the "Lassie" TV series, sometimes even the DVD version isn't very good either.