Should I change the Desktop Wallpaper to avoid pixel burning?

Hi there.

I noticed that my old 30-inch Cinema Display had pixel burning becasue I had the same Desktop Wallpaper all the time, now I have a Thunderbolt Display and I want to avoid this to happen.

Should I setup the desktop wallpaper to change every x amount of time? or is it just my imagination and anyway the pixels just dim and burn with the years?

Thanks!