IMHO good cleaning is needed... But the big thing is wiping off the BCG and paying attention to the bolt face & extractor. Even that isn't a huge deal. If your running wolf ammo or something else thats very dirty... Then just do what I do... Wipe off the BCG, Bolt Face, Extractor and wipe off the inside of the chamber with a rag after ~500 rounds (you can probably push it to 800-1000rnds but you will start to have to use your FA).
When I'm running clean ammo, then I will wipe down after 800-1000rnds (you can push it further if needed).
After the wipe down, lube it up... I like WD40 or CLP in the field (I also make sure i put a little lube on the hammer face).
Now, when your done shooting for the day and your home... Then thats at least when I give it a good cleaning... I get in there really well on everything and clean it to the point that it's once again "Factory Clean" and ready for next time.
Something else to keep in mind, If you have a FailZero BCG, or fully Chromed BCG then your field cleaning's after high round counts can be spaced out even more and will go MUCH faster. Yes, they are more expensive... but a fantastic upgrade to any AR that is in constant use with high volume round counts.
I even consider it a cost saving measure... Because I can simply wipe off my Chromed BCG's I end up using 1-2 heavy duty paper towels in doing a majority of my BCG cleaning. Thus... I use less Q-tips, less solvent, spend less time, etc...