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If a tiny change forces a huge view to rebuild, scrolling stutters. The fix is to keep each redraw as small as possible.

Put @State in the smallest view that owns it. Then only that little view re-evaluates when the value flips, not its big parent.

Break a large body into smaller subviews. SwiftUI can then diff and skip the pieces whose inputs did not change.

Hand a subview just the values it reads. The fewer dependencies a view has, the less often it must recompute.

With @Observable models, a view updates only for the exact properties it touches. Read just the fields you display.

One giant model read everywhere makes every change ripple outward. Split it so each view depends on a narrow slice of data.

A closure that reads many properties widens a view's dependencies. Capture only the specific value the action truly needs.

Never do expensive computing inside body. It runs often, so cache results in state or a model and read the finished value.

Mark unchanging inputs as let. Constant properties never trigger updates, signaling clearly that they cannot cause a redraw.

For costly subviews, make them Equatable so SwiftUI can compare inputs and skip re-evaluation when they match.

Do not guess. Scope state, extract views, then measure to confirm you actually shrank the redraws that hurt.

You learned to scope state tightly, extract subviews, pass minimal data, and keep body cheap. Smaller dependencies mean fewer redraws. ⚡