I've always stored in zip-lock bags, which probably offered a little more protection from the atmosphere, but had success with ten year olds.
Some folks are paying major mucho dinero for vintage transfers on ebay, We're talking 1980's. So, they must figure they will be fine as well.
Obviously, you are in a position to test, and not only check adhesion with a laundering, but can also adjust time, heat, or pressure as needed.