Need is the key here.
I don't lube the bore all the time. it depends on air temperatures, and relative humidity.
Nov.-Dec., our primary months for hunting upland game here, tend to be foggy, damp months. Decembers get down right cold!
I learned my lessons the hard way. I first learned that my water based lubed patch would freeze if carried in my hunting bag instead of in a pocket next to my body under my jacket. NEXT, I learned that sub-freezing air is so dry that it will suck the water right out of our patch, and leave a rust "ring" where the PRB is seated over the powder. :cursing:
I learned with a modern shotgun that mist, fog, and drizzle are enough to leave rust spots in and outside the barrel after a day's hunting when no shots are fired, and its freezing out. Snow did it on that one occasion. I had the same experience on my MLer rifle barrel in a drizzle, when it was just above freezing, and another time when hunting in hot weather during shifting on- and-off drizzle, fog, mist, rain-- kind of day.
My lube was water, water soluable oil, and Lestoil, I Now use Young Country 101 Lube, an early version of "WonderLube", or any mix of veg. oil and beeswax. I have also used plain water, spit, Hoppes Black Powder solve and lube, and any number of commercial products.
There is no " Must use", or "Right " and "Wrong" to this issue. There are plenty of places where people live and hunt in this country where rust is not much of an issue. :shocked2: :idunno:
Keep an eye n the weather, ranges of temperatures, and relative humidity when you plan your hunt, and act accordingly. :hatsoff: