I don't know about going bad, but I had fuel loss recently. Last winter I purchased 42 gallons of fuel when prices were low [$1.68 per gallon] I stored this fuel in six 5 gallon plastic fuel cans, purchased at Home Depot. I also stored 12 gallons of it in two NATO steel cans. I added StaBil to the fuel in all 8 cans and placed the cans up into my shop's loft.
I purchased the fuel to ensure that I would have a hurricane emergency supply for my generator. I live in SE Florida. Over the past month, I started using this fuel in my car, as the likelihood of a hurricane this year in Florida has past. In three of the six plastic cans, the fuel had partially evaporated and/or vented. This was due to a less than perfect seal between the plastic cap and the plastic can. It was also exacerbated by the high heat we experience during the summer months here. The heat caused the cans to pressurize, spilling fuel out of the poorly sealed plastic cans. I lost between 2 quarts and 2 gallons of fuel on three of the six plastic cans. The two steel NATO cans had considerable pressure in them, but not one drop of fuel had escaped.
This is not scientific, just my personal data point.
Charlie Kuss