It depends on ester content FC. Full-syn 2T premix oils degrade if exposed to air because of the volatile esters used. I presume you're talking about SE full-syn 20W50 motor oil...it'll last virtually forever if the container is full. Most quality ester-based full-syns have a sealed cap so they'll keep indefinitely. A bit of Glad-wrap under the cap and they're fine for years.

With you Nutty

Hey Soapbox, fucking hilarious, never thought of that, er, accept that synth is kinda new. No matter still fucken funny. 

Temperature controlled would be beneficial on any product, get turned over every 6 months by me ? Good question FC, ripper answer by Soapy !

He he. Ripper. 

Mobile One has a shelf life ( use by date.

I spoke to a tech-chemist mate at Mobil about this KK. Mobil testing has found that the plastic oil containers breathe, no matter how well they're sealed. This causes the detergent component of the oil (which is based on a very reactive metal, sodium, phosphorous, etc) to partially oxidise over time, decreasing the detergents' efficiency. To avoid this issue Mobil package their aviation and race-spec products in sealed steel containers. I guess SE are onto the same issue.