I would like to have my own storage tank and use the same vendor exclusively so that fuel quality could be less of a mystery.But,as of yet,I'm forced to buy my fuel "on the road" where you really don't know for sure what you're getting until it's too late.
I use additives 100% of the time during the winter.I know that NO supplier adds enough additives,or blends in enough #1,to prevent icing and gelling when the temp drops well below zero.Added to that the fact that diesel fuel has a high propensity for water contamination,and you're left on the side of the road trying to thaw frozen fuel lines and change filters at 25 below.I've had it happen many,many times.Most winters it happens at least once.
Since most heavy equipment isn't operated at -25 that scenario shouldn't be an issue.But the water contamination problem could be even worse with a storage tank that has low fuel turnover,and/or isn't monitored closely.If you happen to fuel,especially just after the tank was filled and any water present has been stirred up enough to become suspended in the fuel,you could get water in you equipment.With enough additives the water can be encapsulated into small droplets,and kept from being absorbed into the filters,or possibly getting through the filters,and splitting an injector.(injector tips can/will split if water is compressed within the injector.)
So,for extreme cold or water contaminated fuel,I'd think additives are almost a necessity,and it's doubtful the supplier/vendor could predict either problem very accurately,without personally monitoring your storage tank,or knowing the weather conditions when the fuel will be burnt.Also,water is where the bacteria that grows in fuel starts at(the thin layer where water and fuel meet),and it can grow to ruin all the fuel in a storage tank.Additives can help control that too,if the supplier hasn't already added any.
If you've a clean storage tank,water trap dispenser filters,no extreme cold operating,then extra additives may be a waste of money.
But then there's still the low sulphur/low lubrication question??????