my .02 on my 5-6K yr stored for winter car.
I change it every 9 months (OLM would let me go 12) this is 4x in 3yrs or one more time than Fords suggestion. The 1 extra every 3 yrs helps me sleep better without being too excessive. If mine was going to be up in Jan/Feb I would change it out b4. My storage is weather dependent but early/mid Dec-mid March
2012 V6 with suspension, shifting, stopping and sound mods.