Remember that in civilian world more barrels of worn out by cleaning than by shooting.

The way it happens in our house is as follows:

Sniper rifle -- cleaned every outing ( non stainless barrel)
AR 15 -- cleaned every few hundred rounds (stainless barrel)
shiny revolver -- once or twice a year
blue revolver -- every time it is used, unless it is going to be used again within a couple of days
rimfire -- action when it gets scabby, barrel almost never (every thousand/few thousand rounds)
SLR -- oily rag everytime, properly cleaned occasionally
7.62 x 39 bolt action -- every time with surplus ammo, oily rag every outing otherwise and then cleaned every few hundred ( chrome-lined)
black powder -- properly, everytime!
SIG P226 -- maybe once a year/every thousand rounds