User blog comment:Sjjtitan2019/Itemization and Build Paths/@comment-8468980-20140107024146

Here's a better explanation of what to build for ADCs.

First big item: Bloodthirster, IE, TF, or Bork. Your first big item should supply you with a healthy dose of AD. AD allows you to last hit better, trade AAs in lane better, and fuel your AD ratios better. Champs that have great AD ratios, or lots of AD ratios synergize with BT, champs with build in attack speed buffs synegize well with an early IE. Both IE and BT are great first buys on all ADCs in any event. TF and Bork are special cases. TF synergizes well with champs who can harass with spells frequently and take advantage of phage's bonus MS, Ezreal and Corki are prime examples. Bork isn't an item you should aim to build early on, that said, if your enemy is not giving you a lot of opporunities to farm and you're behind in damage then bork is an excellent economy buy. For the same price (or less!) as the other big guys, you get AD, attack speed, lifesteal, a scaling on-hit, and an extremely versatile active.

Second big item: Zeal into Stattik shiv or PD. Second big item should be your workhorse attack speed item. Shiv is less expensive and helps to push a lane greatly, while PD allows you to pass through enemy units and grants greater damage stats. Both are great items, I discourage ADC players from buying both especially one right after the other.

Third big item: Last Whisper because armor. Raw HP stacking isn't really a thing anymore so Bork isn't really competing for this spot atm. If your enemies decide to stack hp foolishly, then Bork is a good item to pack.

Fourth item: If you bought IE as your first item, build BT now. If you bought BT as your first item, build IE now.

Defensive item: GA is a free one up in team fights, Randuin's provides an excellent mix of mitigation and the active lets you self peel all melees, BV allows you to flip the bird at highly combo-dependant mages or allow you to walk away from initiations, Maw frustrates most Magic damage-dealers, Frozen Mallet for its versatile slow, and Scimitar is a free cleanse.

Build dynamically based on what gold opportunities you've had and what gold opportunities you are likely to have in the near future of the match.