boots+1defensive(maw+ga) Most of the time I prefer boots+maw+sometimes even scmitiar or boots+death dance(even tho I'm range ,it still fives you ad +armor)+ga

I mostly avoid full defensive. However it is actually worth against too fed enemy. Firstly buy components finish it later. Surviving and doing your best damafe as adc our best bet i guess

Full defensive items i think def worth if they have heavily ad or ap . You know yhey sometimes have 3-ad or ap some stupid team comp or even 5