If your apps are running slow or giving errors, you should try a factory reset.

1. With TV off.  Press Mute-1-8-2-Power and TV should come on with the service menu.  Hit OK on OPTION, OK on Factory Reset and OK again on Factory Reset.  You should just press OK three times in a row.  TV should reset.  Be very careful in the service menu since you can brick your TV changing things.

2. Go through the setup wizard and complete it to the end

Backlight failure is common in LED TVs. Keeping the backlight level at around 55% will make them last. I would also recommend turning off eco sensor which automatically adjusts the backlight level based on the ambient light.

3. Turn off Eco Sensor: Menu ->System->Eco Solution  – Turn Eco Sensor OFF
4. Turn down the Backlight: Menu -> Picture  Set Backlight level to between 10-12.  It should apply to all sources by default.

Motion smoothing will sharpen images for fast actions like sports but will make movies too sharp and look like soap operas.
5.  Menu -> Picture ->Picture Options  Turn OFF LED Clear Motion