Incandescent (filament) bulbs glow by black-body radiation as the filament heats. Mains cycles are too short for the bulb to flicker (though you can get interesting effects on slower, ~2Hz or thereabouts, voltage fluctuations).
Fluorescent and LED lighting actually flicker multiple times per second, though this can be tuned somewhat.
If you remember CRT displays and monitor flicker, the problem wasn't so much the flicker rate of the monitor, but the interference in rates and timing between your monitor and the overhead office fluorescent lighting. Setting refresh to anything other than (and preferably above) 60Hz (US) would resolve this.
I'm sure I remember my parents calibrating their turntable under incandescent lights, though... maybe it was their halogen up-lighter instead of their standard incandescent ceiling light? It definitely worked with one light in their living room but not the other.
Aren't LEDs fed with DC? If so they would obviously not flicker but I'll admit not cracking my LED bulbs open just to see, as they're expensive enough.
LEDs are DC. What I've observed in certain applications, particularly LED taillights/brake lights, is a flicker pattern which I suspect is either an AC/DC conversion artifact, or a brightness regulation. I find it quite distracting.
It's also fairly well known that LED's response to voltage variation is fast enough to be of concern in highly secure data environments. Demonstrations have been made of reading line signal from modems, and even Ethernet and other high-bandwidth networking equipment status/indicator lights.
LEDs are generally fed with DC, as current only flows in one direction, but they flicker as the power coming into them fluctuates -- the more ripple, the more flicker.
Cheap LED holiday lights don't even bother rectifying the AC voltage across the lights, so they are only on for half the cycle, giving them a very noticeable flicker. It's especially apparent as you scan your eyes past them.
In contrast, incandescents allow current to flow both directions, and will glow for a little while after current stops flowing, so they don't appear to flicker on 60/50hz mains current.
Incandescent (filament) bulbs glow by black-body radiation as the filament heats. Mains cycles are too short for the bulb to flicker (though you can get interesting effects on slower, ~2Hz or thereabouts, voltage fluctuations).
Fluorescent and LED lighting actually flicker multiple times per second, though this can be tuned somewhat.
If you remember CRT displays and monitor flicker, the problem wasn't so much the flicker rate of the monitor, but the interference in rates and timing between your monitor and the overhead office fluorescent lighting. Setting refresh to anything other than (and preferably above) 60Hz (US) would resolve this.