Https://community.usa.canon.com/t5/General-Discussion/KNOW-MORE-52-800-953-0451-How-far-in-advance-is-the-cheapest/td-p/531040https://community.usa.canon.com/t5/General-Discussion/KNOW-MORE-52-800-953-0451-How-far-in-advance-is-the-cheapest/td-p/531040https://community.usa.canon.com/t5/General-Discussion/KNOW-MORE-52-800-953-0451-How-far-in-advance-is-the-cheapest/td-p/531040 https://community.usa.canon.com/t5/General-Discussion/KNOW-MORE-52-800-953-0451-How-far-in-advance-is-the-cheapest/td-p/531040