I see websites saying butter goes 'bad' after a few months in the fridge. How do I know if my butter has gone 'bad?' To me, it can sit in there for a year and still taste, smell, and look exactly the same as when I bought it. They say it goes rancid in a few days out of the fridge, but I take butter camping (in the winter so it's usually cool out) and it seems the same after 2 weeks of no fridge. What about coconut oil? Seems to me, these saturated fat oils are very stable.
Should I really worry about them going bad or is that just the industry being overly cautious and also hoping I will keep buying more if my stock gets old? Now I could see that for grain oils, that stuff is already compromised on arrival and is already bleached and perfumed, so any additional rancidity would probably be more hidden. But again, I just don't recall ever having seen any detectably rancidity even if it's been stored a long time. THe only time a grain oil has ever smelled rancid to me is after it has been heated and cooled many times, like when used as a fry oil at a restaurant. (Can you imagine the level of degradation and rancidity some of those restaurant fry oils must reach after hundreds of high temp heatings!!!)