Spelunking the Internet provides this:
The MFG warranty is 1 year parts and 1 year labor. The life expectancy of LG OLED is 30K hours to 50K hours to half brightness. Only coming from the use/on time of the panel; not from being off. That is 7 days a week, 6 hrs a day to reach 14.5 years to 20 years to half brightness. If a customer watches the TV in Vivid mode they will be closer to the 14.5 year number. If the customer has the OLED calibrated (or run in Cinema mode) they will be at the 20 year to half brightness level. Calibration is not only good for panel life but picture quality also; it is a win win! 2016 models will have substantially increased hours that can not be released until product ships, but I expect them to be brighter
The general rule of thumb is do not leave a static image on the screen for more than 60 minutes; but that can vary depending on the intensity and color of the image. There is no way to fix burn-in once it is at that point. 2016 models will have a picture quality recovery system build into the panels to reduce image retention before it becomes burn-in.
My plasma has that pixel rotation / shifting feature and I've never seen any kind of burn-in on it. Presumably they've mastered the art of shifting the display to prevent burn-in at this point, since OLEDs were available since 2013.
Assuming you watch TV for five hours a day every day, taking the conservative 30k hour number to half brightness, that's 16.4 years.
The argument for waiting
You can probably expect to see more affordable OLED models. In just two years the price of a 55-inch OLED has fallen from $10,000 to $1,800. A model with support for Ultra HD, HDR, and WCG has been selling for $3,000 this fall. Prices won’t continue to drop at that rate, but it is reasonable to expect that in another two years they’ll be selling for much closer to what an LCD costs today. If everything else is equal (resolution, screen size, curved vs. non-curved) then we’d recommend OLED tech for most people because the image really is that much better than LCD.
I looked it up and I paid $1500 for my 47" plasma in 2008 dollars.