In my bad experience with the reusable fittings the main problem was getting the stems to screw into the hose more than half way. The hose would start rotating after that point and the whole system failed.
- - However, after talking to the engineers at the makers of the fittings, they said - "Aren't you using the special arbor tool?" I said, "what arbor tool? Send me one." They said they can't do that, you have to make it yourself and sent me a photo
. At that point I gave up and went back to soft copper tubing. But this was 10 years ago so maybe things are different now.
- - I concluded the problem was that there are variations in the thickness of the hose walls and if the hose wall was just a touch too thick the stem would not screw all the way in. The distributor of the fittings mentioned that they got a lot of returns due to the same problem and were considering stopping to sell the product.