[caseysoftware]

Thanks for this link. I don't particularly like it but this is the clearest explanation that I've seen.

On the plus side, it does encourage them to have a major release every year so they can keep resetting that 12 month clock.

And if it's a trivial "major" release, then you can fallback to the last version without much loss. If it's a useful major release, it's motivation for you to hang around.