I have them, because it's illegal to not have them in some places during the winter months, but they've never been taken out of the bag. Yep, the 'cheap' Chinese kind, but they'll last longer than I will: the tag says "Do not remove from bag" and I don't - when the road's that bad, [as a solo], I stay off till it gets better.
That's happened 3 times in 6 years, and 2 of them, chains wouldn't have helped: the road was closed entirely to everyone, and reopened without chains required.