Is there any standard method for implementing toggleable spells? Cast once and the effect begins, cast again to end the effect?

It seems only armor enchantments and abilities let the spell be "constant effect," so I'm not sure how to go about doing this.

My initial thought is to use a hidden item with a constant-effect enchantment on it, and have the spell add and equip the item if it isn't already, or remove the item if it is. Is there any better way?