i read something about being able to switch boots

I recalled the need for this as i was hoping to get armor tenacity boots. since lets say im warrior and i rush witsend. i dont need any more mr. id get tabis but i want tenacity. the thing that seperates boots from other items is that movementspeed is a must. boots are sort of a tax. if you want to be relevant mid game having tier 2 boots is crucial on certain champions particularly melee. So being able to switch out boots at little to no extra cost would be nice.