Murphy's law says that if you keep them you will never need them, and if you throw them away you will need them immediately.
If it was me, I would keep them for at least a couple years, and then probably eventually throw them away if I had not found a use for them.
Also, welcome to the Forum and to Fiesta ST ownership. I've had the privilege of owning some great cars in my life, but this is one of my favorites. Just to put it in perspective, I like it more than the E90 BMW M3 that I had before it. You're going to enjoy it a lot.