Yep. Don't use expensive, new, pristine, energy-intensive materials wherever possible. Reserve those for finishes and exterior coatings. Appropriate filler mate

Yep. Don't use expensive, new, pristine, energy-intensive materials wherever possible. Reserve those for finishes and exterior coatings. Appropriate filler materials should be suitable for the strength, longevity, and safety profile and function desired. This also reminds me of some DIY and volunteer experiences installing residential fence posts. On a volunteer gig, I saw people using 200 lbs. of concrete and keep adding water until it's soup triumphally proclaim it's "the right way" while dismissing supervisors and others who knew what they're doing. Meanwhile, I was looking at depth, slope, wind risk, and soil (hydrology), and gathering site debris like rocks and chunks of metal to stick under each post so it wouldn't rot in 5 years or become the Big Dig in time, materials, or quality.