"Never Let the Sun Set on a Dirty Gun"
That's always been my motto. Now how thoroughly I clean and lube varies with the amount and type of ammo I've been shooting. Remember that part of cleaning is inspecting for problems and fixing them as necessary. This ensures the gun will continue to operate.
An AR should go many thousands of rounds without cleaning or lubing. But why do it? The only time such a situation should occur is when a band of bad guys is chasing you around in some hellhole. Remember that dirt mixed with oil and grease becomes, over time, nothing more than lapping paste that will in fact wear away the surfaces.
If you want to shoot...shoot...don't talk! Tuco
USAF Munitions 1969-1992