seniorObjective-C
What is the cost of excessive KVO usage in large apps?
Updated May 17, 2026
Short answer
KVO introduces runtime overhead due to dynamic subclassing and observer tracking.
Deep explanation
Each observed object becomes a dynamic subclass via isa-swizzling. Notifications trigger method interception chains. In large apps, excessive KVO leads to memory overhead, debugging complexity, and crash risks from missing observer removal.
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