I clean and oil my firearms after every use. If I’m dragging them through wet brush, I'll disassemble, dry and re-lube even if I haven’t fired. If I only put a round or two, I "may" just run a bore snake down em', but 98% of the time I do a thorough cleaning. Maybe it’s the fumes, but a cleaning and taking apart guns is almost a form of Zen meditation for me.
That said, when I see a friend or anyone for that matter takes poor care of his or her firearm, I get truly shocked and horrified. A friend of mine didn’t clean his battle rifle after a box of corrosive .308's. Months later, I find out the barrel's completely rusted over. It’s not my gun, but I couldn’t talk to him for weeks afterwards. I still get choked up every time I think about it.