diff --git a/README.md b/README.md
@@ -36,7 +36,7 @@ PythonNative is a cross-platform toolkit for building native Android and iOS app
 - **Hooks and function components:** Manage state with `use_state`, side effects with `use_effect`, and navigation with `use_navigation`, all through one consistent pattern.
 - **Typed `style` prop:** Pass all visual and layout properties through a single `style` dict, fully described by the `pn.Style` `TypedDict` and the ergonomic `pn.style(...)` helper for IDE autocomplete and static checking. Compose reusable styles with `StyleSheet`.
 - **Cross-platform flexbox engine:** A pure-Python, Yoga-style layout engine computes frames once and applies them to native views, so `flex`, `padding`, `aspect_ratio`, and `position: "absolute"` produce the same geometry on Android and iOS.
-- **Virtual view tree + reconciler:** Element trees are diffed and patched with minimal native mutations, similar to React's reconciliation.
+- **Virtual view tree + reconciler:** Element trees are diffed and patched with minimal native mutations, similar to React's reconciliation. State updates re-render **locally** — only the component whose state changed (and its subtree) re-runs, and unchanged leaves reuse cached intrinsic measurements — so deep UIs stay responsive instead of re-rendering the whole app from the root on every tap.
 - **Direct native bindings:** Python calls platform APIs directly through Chaquopy and rubicon-objc, with no JavaScript bridge.
 - **Custom-component SDK:** Wrap any platform widget as a first-class element with type-checked props via `pythonnative.sdk` (`Props`, `@native_component`, `element_factory`). Plugins distributed on PyPI auto-register through the `pythonnative.handlers` entry-point group.
 - **CLI scaffolding:** `pn init` creates a ready-to-run project; `pn run android` and `pn run ios` build and launch your app.

diff --git a/docs/concepts/architecture.md b/docs/concepts/architecture.md
@@ -19,9 +19,14 @@ platform APIs synchronously from Python.
 3. **Reconciler.** On first render, the
    [`Reconciler`][pythonnative.reconciler.Reconciler] walks the tree
    and creates real native views via the platform backend. On
-   subsequent renders (triggered by hook state changes), it diffs the
-   new tree against the previous one and applies the minimal set of
-   native mutations.
+   subsequent renders it diffs against the previous tree and applies
+   the minimal set of native mutations. State-driven renders are
+   **local**: a setter marks only its own component subtree dirty, and
+   [`flush_dirty`][pythonnative.reconciler.Reconciler.flush_dirty]
+   re-runs just those components instead of the whole app from the
+   root (the full tree is only rebuilt on mount, navigation, and hot
+   reload). Sibling and ancestor components whose state did not change
+   are left untouched.
 4. **Post-render effects.** Effects queued via
    [`use_effect`][pythonnative.use_effect] are flushed **after** the
    reconciler commits native mutations, matching React semantics.
@@ -78,15 +83,29 @@ and a new one is created.
 
 ### Render lifecycle
 
-1. **Render phase**: component functions execute. Hooks record state
-   reads, queue effects, and register memos. No native mutations
-   happen yet.
-2. **Commit phase**: the reconciler applies the diff to native views,
-   creating, updating, and removing views as needed.
-3. **Effect phase**: pending effects are flushed in depth-first order
+1. **Schedule phase**: a `use_state` / `use_reducer` setter that
+   actually changes a value marks its owning component dirty (adding
+   the component's node to the reconciler's dirty set) and asks the
+   screen host to schedule a flush. Several setters coalesce into one
+   flush.
+2. **Render phase**: only the dirty components execute, shallowest
+   first so a dirty ancestor's re-render subsumes any dirty descendant.
+   Each dirty component re-runs its body against its preserved hook
+   state, with the context stack of every enclosing `Provider` restored
+   so [`use_context`][pythonnative.use_context] still resolves. Hooks
+   record state reads, queue effects, and register memos. No native
+   mutations happen yet.
+3. **Commit phase**: the reconciler applies the diff for each
+   re-rendered subtree to native views, creating, updating, and
+   removing views as needed, and bubbles any swapped subtree-root view
+   up to its nearest native container.
+4. **Layout phase**: a layout pass recomputes frames. Leaves whose
+   `Element` is unchanged reuse a cached intrinsic measurement, so
+   untouched subtrees skip native `measure_intrinsic` calls.
+5. **Effect phase**: pending effects are flushed in depth-first order
    (children before parents). Cleanup functions from the previous
    render run before new effect callbacks.
-4. **Drain phase**: if effects set state, a new render pass is
+6. **Drain phase**: if effects set state, another flush is
    automatically triggered and the cycle repeats (up to a safety
    limit to prevent infinite loops).
 

diff --git a/docs/concepts/lifecycle.md b/docs/concepts/lifecycle.md
@@ -15,15 +15,22 @@ A render pass is triggered by:
 - A navigation event (`navigate`, `go_back`, `replace`).
 - A hot-reload module swap (see [Hot reload guide](../guides/hot-reload.md)).
 
+A `use_state` / `use_reducer` setter re-renders **locally**: only the
+component that owns the changed state (and the subtree it returns) is
+re-run, not the whole app. The full tree is rebuilt from the root only
+on initial mount, navigation, and hot reload. Sibling and ancestor
+components keep their existing native views and hook state untouched.
+
 The phases:
 
-1. **Render**. Your `@component` function runs. Hooks register state,
+1. **Render**. The affected `@component` function(s) run — for a state
+   change, just the component whose setter fired. Hooks register state,
    queue effects, and capture closures. No native widgets change yet,
    so this phase is cheap and pure (modulo `use_state` updates).
 2. **Commit**. The
-   [`Reconciler`][pythonnative.reconciler.Reconciler] diffs the new
-   tree against the previous one and applies the smallest set of
-   native mutations through the registered
+   [`Reconciler`][pythonnative.reconciler.Reconciler] diffs the
+   re-rendered subtree against the previous one and applies the
+   smallest set of native mutations through the registered
    [`ViewHandler`][pythonnative.native_views.base.ViewHandler]s.
 3. **Effects**. Cleanup callbacks from the *previous* render run
    first; new [`use_effect`][pythonnative.use_effect] callbacks run

diff --git a/src/pythonnative/hooks.py b/src/pythonnative/hooks.py
@@ -76,6 +76,8 @@ class HookState:
         "_trigger_render",
         "_pending_effects",
         "_dirty",
+        "_vnode",
+        "_reconciler",
     )
 
     def __init__(self) -> None:
@@ -95,6 +97,13 @@ def __init__(self) -> None:
         # knows that a memoized component still needs to re-render even
         # when its props didn't change.
         self._dirty: bool = False
+        # Back-references wired by the reconciler so a state setter can
+        # mark *its own* component subtree dirty for a local re-render
+        # (instead of forcing a whole-app re-render from the root). Both
+        # stay ``None`` until the component is mounted, and are cleared
+        # again when it unmounts.
+        self._vnode: Any = None
+        self._reconciler: Any = None
 
     def reset_index(self) -> None:
         """Reset every per-hook cursor to ``0``.
@@ -182,6 +191,25 @@ def _schedule_trigger(trigger: Callable[[], None]) -> None:
         trigger()
 
 
+def _notify_state_changed(ctx: "HookState") -> None:
+    """Mark ``ctx``'s component dirty and schedule a render after a state change.
+
+    Enqueuing the owning ``VNode`` in the reconciler's dirty set is what
+    makes the subsequent render *local*: the screen host's trigger calls
+    ``flush_dirty``, which re-renders only the components marked here
+    rather than the whole app. The dirty mark is eager (so several
+    setters coalesce), while the render trigger respects
+    [`batch_updates`][pythonnative.batch_updates].
+    """
+    ctx._dirty = True
+    reconciler = ctx._reconciler
+    vnode = ctx._vnode
+    if reconciler is not None and vnode is not None:
+        reconciler.mark_dirty(vnode)
+    if ctx._trigger_render:
+        _schedule_trigger(ctx._trigger_render)
+
+
 @contextmanager
 def batch_updates() -> Generator[None, None, None]:
     """Coalesce multiple state updates into a single re-render.
@@ -272,9 +300,7 @@ def setter(new_value: Any) -> None:
             new_value = new_value(ctx.states[idx])
         if ctx.states[idx] is not new_value and ctx.states[idx] != new_value:
             ctx.states[idx] = new_value
-            ctx._dirty = True
-            if ctx._trigger_render:
-                _schedule_trigger(ctx._trigger_render)
+            _notify_state_changed(ctx)
 
     return current, setter
 
@@ -339,9 +365,7 @@ def dispatch(action: Any) -> None:
         new_state = reducer(ctx.states[idx], action)
         if ctx.states[idx] is not new_state and ctx.states[idx] != new_state:
             ctx.states[idx] = new_state
-            ctx._dirty = True
-            if ctx._trigger_render:
-                _schedule_trigger(ctx._trigger_render)
+            _notify_state_changed(ctx)
 
     return current, dispatch