User blog comment:TheTobarMethod/Do AP's Need A QSS Upgrade?/@comment-6301771-20130904021805/@comment-5556439-20130907203302

Do you even understand the concept of build efficiency and being time effective? Thats why Kog isnt popular at all. He is useless until he gets that 3rd item and even then hes so-so.

Example:

Kassadin- Needs mana/regen to reach full lane/roaming strength, but also defense because hes melee. Catalyst solves both mana and HP = better buy than tear. He buys It at around 5 minutes in, so hes solved his issues before he even needed to WITH time and gold to spare. Catalyst is now better than Tear for Kass.

Zhonyas? Buys armguard 7 minutes in. Solves defense issue, but doesnt give much outside of it. If not laning vs an AD 70% of the entire purchase is wasted, the AP at that point wont do much if anything. Your still 1600 gold from the reason you bought Armguard, thats a lot of farming. Point? Kass needs the sustain before the damage/survivability because his kit gives him enough as is.

Only a handfull of champions buys Zhonyas 1st: Kennen, Fiddle, Swain, etc have perfect reasons for rushing it.

Making Zhonyas a core item on every AP early on in the game is a dumb idea unless they really make use of the entire buy. Many champions need Deathcap, Lich Bane, DFG, etc before Stasis. Why buy Hourglass if they dont have dive, why buy Armguard early if your against an AP, why buy Hourglass if your long range like Lux or Brand? Its wasteful.

You want to get maximum efficiency from a buy if its going to be early, and early on you need to benefit from EVERY STAT greatly for the purchase to be worth it. Zhonyas is only 100% worth it if your vs an AD or dive heavy team. Example would be Elder Lizard on junglers. They benefit from literally every stat and effect it gives. Even though its not very good past early game, its still an awesome purchase for pre-20 minutes.

THATS why its situational. And with that said, every item in the game besides pure damage on a Carry is situational. You need to buy acording to what you need and what your dealing with. Some champions ignore this rule and always buy a certain item first but usually they buy something that gives stats similar to that ONE item they usually buy.