Depends on what I am shooting. 22LR? Clean when the carbon starts to foul the action, or leak down onto my hand! (GRIN) But I also shoot 7.62 and 8mm CORROSIVE primed- clean immediately after shooting. Others in prep for storage, etc. Ref: patch= bullet, well, I clean from the breech- push a wet patch thru, and DO NOT pull it back thru. Jacketed bullets will leave metal fouling. I shoot a lot of soft lead wadcutter, and use a Lewis De-leader at least once a season. My auto pistols? Clean and lube after a shooting session. One exception is a Winchester Mdl 100- the gas system on that should never be put away dirty. Action gets pulled, weapon cleaned every session it gets fired. Go to the range, watch the benchrest shooters.