I shoot mostly benchrest, and in a 6mmBR long range rifle I clean after two or four targets, depending on my mood. I don’t notice a difference if I clean within 50 rounds of fire.
I agree with Roland, and I use the TK Nolan bore guide. It is expensive, but it will last forever, and it gives me the feeling that I’m doing all I can to prevent barrel damage from cleaning.
I have for the last year been using a combination of Hoppes and Kroil to clean my rifles, and I don’t know of anything that works better. I mix it in small applicator bottles in a ratio of two parts Hoppes to one part Kroil, and it really seems to do the job well. If I have time when cleaning at home, I let it sit in the bore for a day or two after I have thoroughly cleaned it, and sometimes I get a little more fouling out and other times it is totally clean. I have a Hawkeye bore scope, and if I look and the bore has a brown hue to it, indicating a carbon buildup, I will put Iosso on a tight fitting patch and short stroke it through the bore. At this point the bore is shiny clean.
If you will take a fiber brush that is slightly bigger than your neck in the chamber and put some bore tech carbon remover on the tip of the brush, insert it in the neck of the chamber and rotate it 20 or so times while the barrel is still warm, it will remove all of the carbon ring also.