Amaizing amounts more than 1st thought - I was grinding mirrors 20 yrs ago, $100 for good 10" blanks, 100 on grits, polish ect & a whole lot of manual grinding.
Now-a-days with technology, astro is amazing, but my back pocket struggles more, being on a carers pension last 10 yrs since missus's spinal injury.
I can say Ive used near 10k in the last 3 yrs, not much by average normal means, but a Ship load for this duck