On typical adc who is reliant on using spells 
I build 
then I have a choice of 
and 
what of those two should I build next? (I don't like shiv). Both are beneficial when you have IE, youmuu isn't gold-efficient without active, but PD is just stats.
Worgslarg1 votesYomuumu's on lucian, phamdancer on cait, idk about graves.
Generally, you want an attack speed item second, then last whisper if they are building armor, if not, you want bloodthirster.
ValyrianBlade2 votesYou want to get that extra crit item before BT. If you're going IE then BT you might as well start with BT as the sustain is more valuable in Lane and in fights (outside of lucky consecutive crits, 1/16 chance of 2 in a row). The reason IE is a good first buy is because of the power spike when you get PD which not only makes you crit 55% but increases AS significantly to get more chances to crit (you need IE before PD because AS and crit chance aren't worth much without the base AD increase.
I wouldn't go ghostblade outside of lucien or vayne (maybe a few others) and if you're going with it then BotRK is probably better than BT. I'll often grab LW third unless no one on the other team has started anything defensive in which case I'll go BT or sometimes Guardian Angel. If they still haven't started armour after that point I'll consider ghostblade over LW since the percent armour pen isn't very helpful compared to flat (equal at 50 armour I think? ) and the extra crit chance and move speed active from ghostblade is a good way to punish them for not building armour.
Worgslarg1 votesI reccomended ghostblade on lucian simply for the CDR, and it's active scales well with the culling.
cshakes1 votesBuy a Shiv on Graves. Shiv gives greater burst, and Graves is all about burst. Lucian is, too, so Shiv is good on him, too. A Youmuu's is good on Lucian, too, since his ult scales off attack speed.
