How good in the long term are compression fit shut-off valves (for toilets and bathroom sinks) vs. good old threaded fittings for leaking? I have always used threaded fittings on 1/2" copper and wrenched on threaded 1/4 turn valves but in my new install am considering 1/2" compression for the 2 units for ease of install and final valve orientation. I'd love to know from the pros how good compression fittings really are and how much you trust them.

Thanks.

I am a big fan of ball valves. Have been ever since in a clever bit of industrial marketing where some business was actually conducted at a Christmas party.

On the other hand, the chromed, compression angle stops are great in exposed locations. They are not used that much and seldom leak. Hidden in a vanity, with a compression connection to the faucet, I would go with the threaded ball valves.

How good in the long term are compression fit shut-off valves (for toilets and bathroom sinks) vs. good old threaded fittings for leaking? I have always used threaded fittings on 1/2" copper and wrenched on threaded 1/4 turn valves but in my new install am considering 1/2" compression for the 2 units for ease of install and final valve orientation. I'd love to know from the pros how good compression fittings really are and how much you trust them.

Thanks.
It depends upon the material that's stubbed out. For PVC and galvanized Iron pipe I would use threaded and for copper I would install compression angle stops. That's all we ever used in our new construction when I was out in the field.

I put 1/2 inch male pipe thread copper addapters on the supply lines and then used 1/2 inch female pipe thread angle stops with 1/4 turn valves made by brasscrafters... they sell them at homedepot.