If I ever get hold of a cheap, impaired Kennedy gold proof, I'll let you know after a few years. Then again, I've been carrying an ASE around for at least two years now, and it's showing almost no wear. I thought with .999 silver being softer than coin silver, I would've seen results by now. I guess I must not fidget with it enough.
I know I have had friends from India who have told me that you can't wear "pure" gold chains because the rubbing against your skin will wear them away until they break. 22k gold is popular in India...hmmm...(22/24)(100)=91.67%
There's no question that 90-92% gold wears better than pure gold, that's why they make it. But even pure gold or pure silver isn't as soft as most think it is. Coins were made out of pure gold for hundreds of years, and their durability was just fine.