So, Grassley has a 0% chance of retiring? LA can flip in a democratic wave, but GA/KY/AR can't? WA/CT/OR should be at only likely D due to the possibility of retirements/strong candidates. And I think he's optimistic on NV (for the dems).
I think LA has more to do with the uncertainty about Vitter. Boozman should have a pretty ironclad hold on that seat, though Safe R for KY may be a bit bullish.
Grassley said he's running as of earlier this year, IIRC. Being Judiciary Chairman should be extra motivation to stick around, even if he's just a farmer from Iowa with no law degree.