Cleaning the Bore?

Assuming good quality pellets and a good bore, it's been my experience that barrels seldom need cleaning. One variable is velocity, and since many folks are pushing these soft pellets ever faster, I expect there is a speed at which most of them will begin fouling at a more frequent interval. Conversely, I tuned my HW100 .177 down to 11 fpe a couple of years ago and haven't cleaned the barrel since. That's not scientific and could be merely coincidence. I have owned a couple of barrels that had less than perfect bores and needed cleaning more often. One had to be cleaned as a firearm barrel, using a rod and bronze brush. I expect the only perfect answer is, clean when needed, using proper equipment and technique. In most cases, a pull-through with Ballistol or similar is all that's needed.