I haven't had the courage to "roll my own" since I was a student. My teacher made it clear: "If you're doing a job or something important, buy new cartridges. Don't roll your own." I consider every frame I shoot as important, so I never try to save what is, after all, only a couple of quid.
I agree with you Paul, if you consider how much we spend on the hardware of photography, in terms of results to cut corners on the software by taking risks of using outdated film stock is to me false economy, film is the cheapest part of photography.