Your experience with TFT type displays may be the case for you and
your usage style and your equipment upgrade habits.
I on the other hand have found that protracted TFT display usage of a
"constant" type image will produce a permanent ghosted image that
will not be cleared, this was proven on (2) IC-756-Pro's that where
operated 7X24 for extended periods of time (3-4 Months at a time) in
a long term survival failure test. The only area that was not
effected was the spectrum display area as the image was changing.
The fixed menu areas to this day still have the ghost image visible
when you change to another menu.
My work laptop display screen (Sony Vio) has a "wonderful" ghost
image of our NOC master screen clearly visible when looking at any
other image, this was caused by the first system admin configuring
all of the laptops to keep the display on full time, the systems
admins is no longer with us.
In my mobile use of the 7K I find it a mild irritation that the small
screen is still on while I use the 7 inch external which is a joy to
use since it takes the strain of my eyes and simplifies my focus, it
is one attention getter when others look into your vehicle and first
think that its some form of GPS display.