diff --git a/aerosandbox/atmosphere/thermodynamics/gas.py b/aerosandbox/atmosphere/thermodynamics/gas.py
index 261890d3d..b565c6a94 100644
--- a/aerosandbox/atmosphere/thermodynamics/gas.py
+++ b/aerosandbox/atmosphere/thermodynamics/gas.py
@@ -55,11 +55,6 @@ def __repr__(self) -> str:
 
         return f"Gas (P = {f(self.pressure, 'Pa')}, T = {self.temperature:.6g} K, ρ = {self.density:.6g} kg/m^3, Pv^gamma = {self.pressure * self.specific_volume ** self.ratio_of_specific_heats: .6g})"
 
-    def __eq__(self, other):
-        if self.__class__ != other.__class__:
-            return False
-        return self.__dict__ == other.__dict__
-
     @property
     def density(self):
         return self.pressure / (self.temperature * self.specific_gas_constant)
diff --git a/aerosandbox/common.py b/aerosandbox/common.py
index 8e3cc203d..a57289a78 100644
--- a/aerosandbox/common.py
+++ b/aerosandbox/common.py
@@ -22,6 +22,31 @@ def __init__(self):
         """
         pass
 
+    def __eq__(self, other):
+        """
+        Checks if two AeroSandbox objects are value-equivalent. A more sensible default for classes that represent
+        physical objects than checking for memory equivalence.
+
+        This is done by checking if the two objects are of the same type and have the same __dict__.
+
+        Args:
+            other: Another object.
+
+        Returns:
+            bool: True if the objects are equal, False otherwise.
+        """
+        if type(self) != type(other):
+            return False
+        if set(self.__dict__.keys()) != set(other.__dict__.keys()):
+            return False
+
+        for key in self.__dict__.keys():
+            if np.all(self.__dict__[key] == other.__dict__[key]):
+                continue
+            else:
+                return False
+        return True
+
     def save(self,
              filename: Union[str, Path] = None,
              verbose: bool = True,
diff --git a/aerosandbox/geometry/polygon.py b/aerosandbox/geometry/polygon.py
index 4f92b0609..b7dfa5442 100644
--- a/aerosandbox/geometry/polygon.py
+++ b/aerosandbox/geometry/polygon.py
@@ -19,12 +19,6 @@ def __init__(self,
     def __repr__(self):
         return f"Polygon ({self.n_points()} points)"
 
-    def __eq__(self, other):
-        return np.all(self.coordinates == other.coordinates)
-
-    def __ne__(self, other):
-        return not self.__eq__(other)
-
     def x(self) -> np.ndarray:
         """
         Returns the x coordinates of the polygon. Equivalent to Polygon.coordinates[:,0].
diff --git a/aerosandbox/weights/mass_properties.py b/aerosandbox/weights/mass_properties.py
index e991fb516..262e44599 100644
--- a/aerosandbox/weights/mass_properties.py
+++ b/aerosandbox/weights/mass_properties.py
@@ -294,32 +294,6 @@ def __truediv__(self, other: float) -> "MassProperties":
         """
         return self.__mul__(1 / other)
 
-    def __eq__(self, other: "MassProperties") -> bool:
-        """
-        Returns True if all expected attributes of the two MassProperties objects are exactly equal.
-        """
-        if not isinstance(other, MassProperties):
-            raise TypeError("MassProperties objects can only be compared to other MassProperties objects.")
-
-        return all([
-            getattr(self, attribute) == getattr(other, attribute)
-            for attribute in [
-                "mass",
-                "x_cg",
-                "y_cg",
-                "z_cg",
-                "Ixx",
-                "Iyy",
-                "Izz",
-                "Ixy",
-                "Iyz",
-                "Ixz",
-            ]
-        ])
-
-    def __ne__(self, other: "MassProperties") -> bool:
-        return not self.__eq__(other)
-
     def allclose(self,
                  other: "MassProperties",
                  rtol=1e-5,