For important things I use fresh film and developer, so basically I agree. If I shoot that 37th exposure, it's never important (but since it might be there, I find something to shoot, just not something important - doesn't cost any more to get that half-picture of a rock).

I have to admit I do the "cheap" thing sometimes. For example, I recently acquired a Bronica GS-1 - my first MF (excluding an Holga). It is a totally different animal than what I am used to (Sears KS-2/Ricoh XR7) - so I've mostly used expired film (4:1 ratio). When I feel comfortable with it I will not "cheap out."

When testing for light leaks, or testing an old camera I fixed myself, why not go cheap. I can tell the difference between bad film/developer and a light leak or bad shutter/lens. I certainly can't tell the finer and even moderate details that most on this board can, but enough for my purposes.
I'll also be "cheap" when experimenting or just having fun.

For important things, however, I spend the money.