when they tell you to change the oil every so many miles OR so many months, the time part which is 3 months for most filters is because they are made out of a paper media and after paper gets wet it only takes so long before it starts to fall apart. if the filter you used when you stored it was a paper media i would change it when you get the time.
Amsoil, K&N, and mobil one all use synthetic media. amsoil filters are guaranteed for 25,000 miles or 1 year
have you been to bobistheoilguy.com
Oil filter study - http://people.msoe.edu/~yoderw/oilfilterstudy/oilfilterstudy.html#sdf15 (old but some good info)
409,000 miles without an oil change -
http://www.performanceoiltechnology.com/haywood_grey_409k.htm