Recently I heard a critical response to a fellow artist’s use of some vintage wood in a design. They used 100 year-old wood in their art which was deemed a “waste” by the responder.

I wish only to explore what “stops the creative process” at this point.
Why was it a waste to use that rare wood?
“If the wood could be used in a more ‘worthy’ application, then it would be a proper use of the material.” If the wood were made into a fine altar piece or carved doors to a crypt, then it would be something more notable.
Nope.
I wonder in this manner sometimes when I make something new, even one-of-a-kind piece from found objects. Certainly few recycled things I have come a provenance or even an estimation of age. None are any sort of rare things other than they had been “lost”, they piqued my interest, and I re-defined them.
Paint remaining in tubes for fear of waste might deter me if I allowed. The costs of paper, canvas, and brushes do frighten me when I order materials.
But, what if I do not get “it” right?
Do I feel guilty when I fail the materials and decide to start over? Does starting over prove I am un-wise?
Nope and nope.
If every time I failed I stopped the process and cleaned up the materials and placed everything back where it belongs and quit I have only accomplished only an exercise in studio cleaning, and turning off the lights.
Do I fail often?
Yep.
I simply begin again, almost out of reflex. I have yet to understand why starting over is such a “horrid consequence”, a waste. [I’m thinking maybe also stay ahead of deadlines, because missing them qualifies as a “horrid consequence”.]
Why is “waste” such a driving concept?
I think it is rooted in fear of failing. If I mess up this cut, then I’ve ‘ruined’ a piece of 100 year-old wood and the wasting wood cops are sitting in a van outside.
Yep, it is the same with anyone who might mess up vintage lumber or a box of nails.
If the piece of 100 year-old wood rests on the shelf for another hundred years perhaps it will be a buffet for termites.
If and if and if must end. It stops the creative process.
Art is verb, it is about doing.