How long before your 55 gallon drum of oil goes bad?

I use Evinrude XD50 in my 200 hp Evinrude E-Tec engine and am thinking about buying a 55 gallon bulk oil drum. I can save about $10 a gallon compared to the counter price at the store, but I wonder how fast I must use it before it goods bad…or does it ever go bad?

My two fishing buddies and I are sharing the drum and should finish it off in about a year.

Does anybody know the answers? Thanks, Bill