Quick answer

Instead of copying the same six items every match, identify what is stopping your champion from doing their job. Against heavy healing, consider an item that applies Grievous Wounds; against resistance-stacking tanks, consider the penetration suited to your damage; against burst, consider survival before another damage purchase.

Instead of copying the same six items every match, identify what is stopping your champion from doing their job. Against heavy healing, consider an item that applies Grievous Wounds; against resistance-stacking tanks, consider the penetration suited to your damage; against burst, consider survival before another damage purchase.

Choose by problem

Enemy threat What to inspect in the shop How to use the decision
A champion heals through your team's damage Grievous Wounds effect and its application condition Buy an option your champion can reliably apply; coordinate with teammates instead of everyone buying the same effect automatically.
A tank builds a lot of armor or magic resistance Armor penetration for physical damage, magic penetration for magic damage Check which resistance matters against your damage and whether you can reach that target safely.
An assassin or mage kills you before you act Defensive stats or an active effect appropriate to the actual damage and threat Choose a survival option that gives you time to reposition; don't treat an item as a substitute for safe positioning.

Grievous Wounds reduces healing while applied, not all healing forever and not shields. Read the current item tooltip: different items apply effects under different conditions. Penetration also has different forms; compare the current tooltip and your target rather than assuming one purchase beats every tank.

A quick decision before buying

  1. After a fight, identify one problem: did the opponent heal, withstand your damage, or eliminate you before you could act?
  2. Check the scoreboard and damage recap where available. Separate physical and magic damage instead of buying armor or magic resistance by habit.
  3. Open the shop's current item descriptions, compare cost and activation conditions, and decide whether a component is useful now. Your role and available gold matter.
  4. Tell teammates what you can cover. If someone already applies healing reduction reliably, your gold may be better spent on another need; check the actual fight rather than assuming coverage.

Items and balance change across patches and modes. Use this as a decision process for Summoner's Rift, not a permanent build list.

Sources: League Wiki Grievous Wounds · Magic penetration · Example anti-heal item.

Sources