diff --git a/common/vlog.h b/common/vlog.h
index 859b157ce619..bb9fbe0bc7d8 100644
--- a/common/vlog.h
+++ b/common/vlog.h
@@ -13,9 +13,10 @@ namespace Carbon {
 //
 // For example:
 //   CARBON_VLOG() << "Verbose message";
-#define CARBON_VLOG()                 \
-  (vlog_stream_ == nullptr) ? (void)0 \
-                            : CARBON_VLOG_INTERNAL_STREAM(vlog_stream_)
+#define CARBON_VLOG()                             \
+  __builtin_expect(vlog_stream_ == nullptr, true) \
+      ? (void)0                                   \
+      : CARBON_VLOG_INTERNAL_STREAM(vlog_stream_)
 
 }  // namespace Carbon
 
diff --git a/toolchain/base/value_store.h b/toolchain/base/value_store.h
index 010362df7636..5c0a5c1e209e 100644
--- a/toolchain/base/value_store.h
+++ b/toolchain/base/value_store.h
@@ -165,13 +165,13 @@ class ValueStore
 
   // Returns a mutable value for an ID.
   auto Get(IdT id) -> RefType {
-    CARBON_CHECK(id.index >= 0) << id;
+    CARBON_DCHECK(id.index >= 0) << id;
     return values_[id.index];
   }
 
   // Returns the value for an ID.
   auto Get(IdT id) const -> ConstRefType {
-    CARBON_CHECK(id.index >= 0) << id;
+    CARBON_DCHECK(id.index >= 0) << id;
     return values_[id.index];
   }
 
diff --git a/toolchain/parse/tree.cpp b/toolchain/parse/tree.cpp
index 2edaf5141741..2e3a907edb4f 100644
--- a/toolchain/parse/tree.cpp
+++ b/toolchain/parse/tree.cpp
@@ -21,16 +21,6 @@ auto Tree::postorder() const -> llvm::iterator_range<PostorderIterator> {
       PostorderIterator(NodeId(node_impls_.size())));
 }
 
-auto Tree::node_has_error(NodeId n) const -> bool {
-  CARBON_CHECK(n.is_valid());
-  return node_impls_[n.index].has_error;
-}
-
-auto Tree::node_kind(NodeId n) const -> NodeKind {
-  CARBON_CHECK(n.is_valid());
-  return node_impls_[n.index].kind;
-}
-
 auto Tree::node_token(NodeId n) const -> Lex::TokenIndex {
   CARBON_CHECK(n.is_valid());
   return node_impls_[n.index].token;
diff --git a/toolchain/parse/tree.h b/toolchain/parse/tree.h
index 699b25b29cdf..3815a6bcbfd5 100644
--- a/toolchain/parse/tree.h
+++ b/toolchain/parse/tree.h
@@ -115,10 +115,16 @@ class Tree : public Printable<Tree> {
 
   // Tests whether a particular node contains an error and may not match the
   // full expected structure of the grammar.
-  auto node_has_error(NodeId n) const -> bool;
+  auto node_has_error(NodeId n) const -> bool {
+    CARBON_DCHECK(n.is_valid());
+    return node_impls_[n.index].has_error;
+  }
 
   // Returns the kind of the given parse tree node.
-  auto node_kind(NodeId n) const -> NodeKind;
+  auto node_kind(NodeId n) const -> NodeKind {
+    CARBON_DCHECK(n.is_valid());
+    return node_impls_[n.index].kind;
+  }
 
   // Returns the token the given parse tree node models.
   auto node_token(NodeId n) const -> Lex::TokenIndex;
diff --git a/toolchain/sem_ir/constant.h b/toolchain/sem_ir/constant.h
index 1684403e9f3d..a7fef04e50b7 100644
--- a/toolchain/sem_ir/constant.h
+++ b/toolchain/sem_ir/constant.h
@@ -41,7 +41,7 @@ class ConstantValueStore {
   // Returns the constant value of the requested instruction, which is default_
   // if unallocated.
   auto Get(InstId inst_id) const -> ConstantId {
-    CARBON_CHECK(inst_id.index >= 0);
+    CARBON_DCHECK(inst_id.index >= 0);
     return static_cast<size_t>(inst_id.index) >= values_.size()
                ? default_
                : values_[inst_id.index];
@@ -50,7 +50,7 @@ class ConstantValueStore {
   // Sets the constant value of the given instruction, or sets that it is known
   // to not be a constant.
   auto Set(InstId inst_id, ConstantId const_id) -> void {
-    CARBON_CHECK(inst_id.index >= 0);
+    CARBON_DCHECK(inst_id.index >= 0);
     if (static_cast<size_t>(inst_id.index) >= values_.size()) {
       values_.resize(inst_id.index + 1, default_);
     }
diff --git a/toolchain/sem_ir/ids.h b/toolchain/sem_ir/ids.h
index be9d5c912214..daf0405e8127 100644
--- a/toolchain/sem_ir/ids.h
+++ b/toolchain/sem_ir/ids.h
@@ -127,17 +127,17 @@ struct ConstantId : public IdBase, public Printable<ConstantId> {
 
   // Returns whether this represents a constant. Requires is_valid.
   auto is_constant() const -> bool {
-    CARBON_CHECK(is_valid());
+    CARBON_DCHECK(is_valid());
     return *this != ConstantId::NotConstant;
   }
   // Returns whether this represents a symbolic constant. Requires is_valid.
   auto is_symbolic() const -> bool {
-    CARBON_CHECK(is_valid());
+    CARBON_DCHECK(is_valid());
     return index <= FirstSymbolicIndex;
   }
   // Returns whether this represents a template constant. Requires is_valid.
   auto is_template() const -> bool {
-    CARBON_CHECK(is_valid());
+    CARBON_DCHECK(is_valid());
     return index >= 0;
   }
 
@@ -174,14 +174,14 @@ struct ConstantId : public IdBase, public Printable<ConstantId> {
   // Requires `is_template()`. Use `ConstantValueStore::GetInstId` to get the
   // instruction ID of a `ConstantId`.
   constexpr auto template_inst_id() const -> InstId {
-    CARBON_CHECK(is_template());
+    CARBON_DCHECK(is_template());
     return InstId(index);
   }
 
   // Returns the symbolic constant index that describes this symbolic constant
   // value. Requires `is_symbolic()`.
   constexpr auto symbolic_index() const -> int32_t {
-    CARBON_CHECK(is_symbolic());
+    CARBON_DCHECK(is_symbolic());
     return FirstSymbolicIndex - index;
   }