The M16 series really doesn't need all that much cleaning to keep it working, all it really needs is good magazines. That is part of the problem with the military though, magazines are a class IX item. And to most in the ordnance or supply system a magazine is a magazine is a magazine. Serviceable or unservicable if you have a mag, than you have a mag, no need to replace it . Because of this a much larger chunk of magazines in the system are unserviceable, you don't find this out till you do some shooting, and contrary to what many people think about the military most don't do much shooting at all. Than when they do, very few know the M16, because of this they attribute failures to "not cleaning the weapon" vice having a bad magazine.
My daily use routine for my carbine overseas was to shoot it every time prior to leaving the IA base (test firing). Which normally was several times a day, most days of the week, except normally Fridays. Friday was the Iraqi version of Sunday, so those days my team would do its "reset" training. At reset training we would shoot our carry load of ammo during various drills. The only time I cleaned my weapon was after the reset training or after being in contact, yet my M4 worked without issue despite being in an extremely sandy environment in Western Iraq. I didn't clean it everyday, I didn't baby it. All I did was buy new mags prior to deploying (was issued 13 H&Ks, but they were too heavy and for some reason were less reliable in M4s) and put Magpull followers and new CS springs into them. Granted the most I ever shot at one time without cleaning was a little over 300 rounds without cleaning. However, that last cleaning could have been a week ago and after a shamal (mass dust storm).