User blog comment:DamonDraven/Oh, dear Reaver.../@comment-24420226-20141213000302/@comment-24420226-20141213214253

Caster ADC's have another item to rush: Trinity Force. The price tag is large but the components are manageable, and having a phage and a sheen is enough like having the Trinity itself that one can hold out on these two items while waiting to complete it, ahead or behind. For Caster adc's, its not really about boosting their abilities, it's about boosting their spell-heavy attack pattern - which relys on autos as much as spells (hence, IE on Lucian).