It's always funny ro read the wide range of opinions and speculation on IR/burn-in. Too bad there isn't more real information out there backed up by in-depth scientific testing.
Personally I have seen mild IR once in a while on my Panasonic plasma, mostly on a dark screen after turning it off. But I would never notice it in normal viewing, and it seems to go away within seconds when the TV is showing ordinary full-screen changing content. I don't see any need for "whitewashing" or burn-in DVDs. I don't think current Panasonic consumer panels have pixel orbiting, nor do I think it's needed, as all it would do is slightly obscure the shape of temporary IR.
There's a worthwhile IDC white paper available here (http://www.pioneerelectronics.com/pi...0-%20FINAL.pdf
) which reports tests showing that temporary image retention occurs on all the plasma TVs they tested, but also that even the worst deliberate case of IR goes away on all of them within 48 hours of playing ordinary video content.
I've seen some scientific papers on plasma display panel design which suggest that image retention is nothing to do with the phosphors, but rather to do with the dielectric sealing compound, which builds up increasing static charge separation the longer the plasma cell is "on".
All sources agree that the phosphors do decay over time, with a brightness half-life of 30,000 - 100,000 hours, depending on who you believe. If you constantly watch the TV with a 4:3 image with black bars on the side, you will eventually get uneven phosphor wear. But it will take a long time. Some people call that burn-in, but uneven phosphor wear is probably a more descriptive term, since there's no burning going on. If you use grey side bars, that should prevent uneven wear from ever becoming very noticeable.