One thing that should be mentioned is that the powder you are using can make a difference in how often cleaning is needed. For my target rifles that use a relatively clean powder, like H4350, I clean every 250 rounds or so, plus or minus 50 rounds. For a target rifle using a dirtier powder like H1000, or a powder that is known to form carbon rings, like RL16 or RL26, I don't go more than 150-200 rounds. For my hunting rifles, I typically clean once at the end of the season and leave a light coat of oil in the bore. At the beginning of the season, I run a patch through, do a bit of shooting to check zero and re-acquaint myself with the rifle, and then have a fouled barrel for the season. My hunting rifles will typically see less than 50 rounds a tear; my target rifles will have hundreds or 1000+ per year.