I have been reading up on oil shelf life. Should I be concerned about leaving brand new quarts of oil outside in my shed? I live in Michigan where it gets extremely cold.
1-2 winters would be fine. Personally, I don't like having more than 2 years worth of oil stock, normally 12-18 months worth due to getting oil while on sale.
It shouldn't be any problem at all. If it looks good use it. I buy lower unit outboard gear lube by the gallon and it sits in the garage for years. I still use it since my outboards do not take an entire gallon. The garage is heated in the wintertime. I wouldn't be afraid to use your oil.