diff --git a/src/App/Expression.cpp b/src/App/Expression.cpp
index 9b42037db6..4311ab5c2e 100644
--- a/src/App/Expression.cpp
+++ b/src/App/Expression.cpp
@@ -1226,9 +1226,9 @@ void UnitExpression::setUnit(const Quantity &_quantity)
     }
 }
 
-Expression *UnitExpression::simplify() const
+ExpressionPtr UnitExpression::simplify() const
 {
-    return new NumberExpression(owner, quantity);
+    return std::make_unique<NumberExpression>(owner, quantity);
 }
 
 void UnitExpression::_toString(std::ostream &ss, bool,int) const
@@ -1258,9 +1258,9 @@ NumberExpression::NumberExpression(const DocumentObject *_owner, const Quantity
 {
 }
 
-Expression *NumberExpression::simplify() const
+ExpressionPtr NumberExpression::simplify() const
 {
-    return copy().release();
+    return copy();
 }
 
 Expression *NumberExpression::_copy() const
@@ -1439,19 +1439,17 @@ Py::Object OperatorExpression::_getPyValue() const {
     return calc(this,op,left,right,false);
 }
 
-Expression *OperatorExpression::simplify() const
+ExpressionPtr OperatorExpression::simplify() const
 {
-    Expression * v1 = left->simplify();
-    Expression * v2 = right->simplify();
+    ExpressionPtr v1 = left->simplify();
+    ExpressionPtr v2 = right->simplify();
 
     // Both arguments reduced to numerics? Then evaluate and return answer
-    if (freecad_cast<NumberExpression*>(v1) && freecad_cast<NumberExpression*>(v2)) {
-        delete v1;
-        delete v2;
-        return eval().release();
+    if (freecad_cast<NumberExpression*>(v1.get()) && freecad_cast<NumberExpression*>(v2.get())) {
+        return eval();
     }
     else
-        return new OperatorExpression(owner, v1, op, v2);
+        return std::make_unique<OperatorExpression>(owner, v1.release(), op, v2.release());
 }
 
 void OperatorExpression::_toString(std::ostream &s, bool persistent,int) const
@@ -2587,18 +2585,19 @@ Py::Object FunctionExpression::_getPyValue() const {
     return evaluate(this,f,args);
 }
 
-Expression *FunctionExpression::simplify() const
+ExpressionPtr FunctionExpression::simplify() const
 {
     size_t numerics = 0;
     std::vector<Expression*> simplifiedArgs;
 
     // Try to simplify each argument to function
     for (auto it : args) {
-        Expression * v = it->simplify();
+        ExpressionPtr v = it->simplify();
 
-        if (freecad_cast<NumberExpression*>(v))
+        if (freecad_cast<NumberExpression*>(v.get())) {
             ++numerics;
-        simplifiedArgs.push_back(v);
+        }
+        simplifiedArgs.push_back(v.release());
     }
 
     if (numerics == args.size()) {
@@ -2608,11 +2607,15 @@ Expression *FunctionExpression::simplify() const
         for (auto it : simplifiedArgs)
             delete it;
 
-        return eval().release();
+        return eval();
     }
     else
-        return new FunctionExpression(owner, f, std::string(fname),
-                                      std::move(simplifiedArgs));
+        return std::make_unique<FunctionExpression>(
+            owner,
+            f,
+            std::string(fname),
+            std::move(simplifiedArgs)
+        );
 }
 
 void FunctionExpression::_toString(std::ostream &ss, bool persistent,int) const
@@ -2878,9 +2881,9 @@ void VariableExpression::_toString(std::ostream &ss, bool persistent,int) const
         ss << var.toString();
 }
 
-Expression *VariableExpression::simplify() const
+ExpressionPtr VariableExpression::simplify() const
 {
-    return copy().release();
+    return copy();
 }
 
 Expression *VariableExpression::_copy() const
@@ -3083,9 +3086,9 @@ StringExpression::~StringExpression() {
     }
 }
 
-Expression *StringExpression::simplify() const
+ExpressionPtr StringExpression::simplify() const
 {
-    return copy().release();
+    return copy();
 }
 
 void StringExpression::_toString(std::ostream &ss, bool,int) const
@@ -3131,18 +3134,26 @@ Py::Object ConditionalExpression::_getPyValue() const {
         return falseExpr->getPyValue();
 }
 
-Expression *ConditionalExpression::simplify() const
+ExpressionPtr ConditionalExpression::simplify() const
 {
-    std::unique_ptr<Expression> e(condition->simplify());
+    ExpressionPtr e = condition->simplify();
     NumberExpression * v = freecad_cast<NumberExpression*>(e.get());
 
-    if (!v)
-        return new ConditionalExpression(owner, condition->simplify(), trueExpr->simplify(), falseExpr->simplify());
+    if (!v) {
+        return std::make_unique<ConditionalExpression>(
+            owner,
+            condition->simplify().release(),
+            trueExpr->simplify().release(),
+            falseExpr->simplify().release()
+        );
+    }
     else {
-        if (fabs(v->getValue()) >= Base::Precision::Confusion())
+        if (fabs(v->getValue()) >= Base::Precision::Confusion()) {
             return trueExpr->simplify();
-        else
+        }
+        else {
             return falseExpr->simplify();
+        }
     }
 }
 
@@ -3270,9 +3281,9 @@ Expression *RangeExpression::_copy() const
     return new RangeExpression(owner, begin, end);
 }
 
-Expression *RangeExpression::simplify() const
+ExpressionPtr RangeExpression::simplify() const
 {
-    return copy().release();
+    return copy();
 }
 
 void RangeExpression::_getIdentifiers(std::map<App::ObjectIdentifier,bool> &deps) const
@@ -3714,7 +3725,7 @@ std::unique_ptr<UnitExpression> ExpressionParser::parseUnit(
         throw ParserError("Unknown error in expression");
 
     // Simplify expression
-    Expression * simplified = ScanResult->simplify();
+    ExpressionPtr simplified = ScanResult->simplify();
 
     if (!unitExpression) {
         auto* fraction = freecad_cast<OperatorExpression*>(ScanResult.get());
@@ -3730,19 +3741,14 @@ std::unique_ptr<UnitExpression> ExpressionParser::parseUnit(
     }
     ScanResult.reset();
 
-    if (unitExpression) {
-        NumberExpression * num = freecad_cast<NumberExpression*>(simplified);
-
-        if (num) {
-           simplified = new UnitExpression(num->getOwner(), num->getQuantity());
-            delete num;
-        }
-        return std::unique_ptr<UnitExpression>(freecad_cast<UnitExpression*>(simplified));
-    }
-    else {
-        delete simplified;
+    if (!unitExpression) {
         throw Expression::Exception("Expression is not a unit.");
     }
+
+    if (auto num = freecad_cast<NumberExpression*>(simplified.get()); num) {
+        return std::make_unique<UnitExpression>(num->getOwner(), num->getQuantity());
+    }
+    return std::unique_ptr<UnitExpression>(freecad_cast<UnitExpression*>(simplified.release()));
 }
 
 namespace {
diff --git a/src/App/Expression.h b/src/App/Expression.h
index 4f471bd5ab..1c496e370d 100644
--- a/src/App/Expression.h
+++ b/src/App/Expression.h
@@ -487,7 +487,7 @@ public:
      *
      * @return The simplified expression.
      */
-    virtual Expression * simplify() const = 0;
+    virtual ExpressionPtr simplify() const = 0;
 
     /// Visit the expression with a visitor.
     void visit(ExpressionVisitor & v);
diff --git a/src/App/ExpressionParser.h b/src/App/ExpressionParser.h
index 67445c0909..84798abd2f 100644
--- a/src/App/ExpressionParser.h
+++ b/src/App/ExpressionParser.h
@@ -88,7 +88,7 @@ public:
 
     ~UnitExpression() override;
 
-    Expression* simplify() const override;
+    ExpressionPtr simplify() const override;
 
     void setUnit(const Base::Quantity& _quantity);
 
@@ -144,7 +144,7 @@ public:
     explicit NumberExpression(const App::DocumentObject* _owner = nullptr,
                               const Base::Quantity& quantity = Base::Quantity());
 
-    Expression* simplify() const override;
+    ExpressionPtr simplify() const override;
 
     /**
      * @brief Negate the stored value.
@@ -221,7 +221,7 @@ public:
 
     bool isTouched() const override;
 
-    Expression* simplify() const override;
+    ExpressionPtr simplify() const override;
 
     int priority() const override;
 
@@ -274,7 +274,7 @@ public:
 
     bool isTouched() const override;
 
-    Expression* simplify() const override;
+    ExpressionPtr simplify() const override;
 
     int priority() const override;
 
@@ -403,7 +403,7 @@ public:
 
     bool isTouched() const override;
 
-    Expression* simplify() const override;
+    ExpressionPtr simplify() const override;
 
     static Py::Object
     evaluate(const Expression* owner, int type, const std::vector<Expression*>& args);
@@ -465,7 +465,7 @@ public:
 
     bool isTouched() const override;
 
-    Expression* simplify() const override;
+    ExpressionPtr simplify() const override;
 
     std::string name() const
     {
@@ -540,9 +540,9 @@ public:
 
     void setPyValue(Py::Object pyobj);
     void setPyValue(PyObject* pyobj, bool owned = false);
-    Expression* simplify() const override
+    ExpressionPtr simplify() const override
     {
-        return copy().release();
+        return copy();
     }
 
 protected:
@@ -568,7 +568,7 @@ public:
                               const std::string& _text = std::string());
     ~StringExpression() override;
 
-    Expression* simplify() const override;
+    ExpressionPtr simplify() const override;
 
     virtual std::string getText() const
     {
@@ -602,7 +602,7 @@ public:
 
     bool isTouched() const override;
 
-    App::Expression* simplify() const override;
+    ExpressionPtr simplify() const override;
 
     Range getRange() const;
 
diff --git a/tests/src/App/Expression.cpp b/tests/src/App/Expression.cpp
index 56db683e03..4eed2370d7 100644
--- a/tests/src/App/Expression.cpp
+++ b/tests/src/App/Expression.cpp
@@ -372,7 +372,7 @@ TEST_F(Evaluate, test_evaluate_simple)
 TEST_F(Evaluate, test_simplify_simple)
 {
     App::ExpressionPtr e = App::ExpressionParser::parse(this_obj(), "1 + 2");
-    App::Expression* simplified = e->simplify();
+    App::ExpressionPtr simplified = e->simplify();
     EXPECT_EQ(e->toString(), "1 + 2");
     EXPECT_EQ(simplified->toString(), "3");
 }
@@ -388,7 +388,7 @@ TEST_F(Evaluate, test_evaluate_function)
 TEST_F(Evaluate, test_simplify_function)
 {
     App::ExpressionPtr e = App::ExpressionParser::parse(this_obj(), "sqrt(4)");
-    App::Expression* simplified = e->simplify();
+    App::ExpressionPtr simplified = e->simplify();
     EXPECT_EQ(e->toString(), "sqrt(4)");
     EXPECT_EQ(simplified->toString(), "2");
 }
@@ -408,7 +408,7 @@ TEST_F(Evaluate, test_simplify_refer_to_var)
     auto* prop = freecad_cast<App::PropertyFloat*>(this_obj()->addDynamicProperty("App::PropertyFloat", "Var"));
     prop->setValue(2.0);
     App::ExpressionPtr e = App::ExpressionParser::parse(this_obj(), "sqrt(2 + Var)");
-    App::Expression* simplified = e->simplify();
+    App::ExpressionPtr simplified = e->simplify();
     EXPECT_EQ(e->toString(), "sqrt(2 + Var)");
     EXPECT_EQ(simplified->toString(), "sqrt(2 + Var)");
 }