After checking various vendor websites, the general shelf life of home
heating diesel fuel is suggested to be 3 months (most conservative
suggestion) to about 2 years. This is depending on whether or not
specific preservatives or additives have been mixed into the fuel to
prolong the shelf life, and the quality of the oil (how it was made,
by cracking, biodiesel, etc.). Regardless of initial shelf life, one
company, PRI, makes an additive (named PRI-D for diesel, but they also
have PRI-G for gasoline) which can be used to retreat diesel fuel
every 18-24 months allowing stored diesel fuel to be used effectively
for an extended 2-10 years (depending on initial quality of fuel).
More information follows below linked:
Thank you for your question.