The BCD396T uses LEDs to illuminate the screen. I wouldn't worry about them wearing out. I have a Realistic PRO-2026, which is almost 15 years old, and it uses a light bulb to light up the screen. It hasn't burned out the lamp yet. (It'll probably burn out tomorrow now that I said that.) My scanners run virtually 24/7 and I haven't had any backlight problems with any of them yet.
Mark