It depends on the gun.Some of mine lose accuracy after 50 or so rounds and some will shoot who knows how many without any problems.My carry 1911 gets it every two weeks of carry time,but I carry it on the farm a lot and it gets dirty and dusty.The AR gets it about once a month regardless of how many rounds are put through it.Hunting rifles get the outside wiped down every trip afield.Some types need stripped down to get cleaned up good while others don't.I don't like to take any of my better shooting bolt rifles out of the stock until it's neccessary.Any used gun gets taken apart,cleaned and inspected,sometimes before I'll buy it.If the deal doesn't go through,at least the seller to be will get a free cleaning.The last used Bushmaster I bought belonged to a local Deputy,and it was sterile when I popped the pin.To each his(or her) own,but clean means reliable to me.