diff --git a/training/trainer.py b/training/trainer.py
index e624283..07a8da6 100644
--- a/training/trainer.py
+++ b/training/trainer.py
@@ -169,16 +169,11 @@ class Trainer:
                     "val_neg_sim": val_metrics["mean_neg_sim"],
                 })
 
-                # Checkpointing based on separation (primary) or loss (secondary)
-                improved = False
+                # Checkpointing based on separation (gap between pos and neg similarity)
+                # This is the key metric for contrastive learning quality
                 if val_metrics["separation"] > self.best_val_separation + self.config.min_delta:
                     self.best_val_separation = val_metrics["separation"]
-                    improved = True
-                elif val_metrics["loss"] < self.best_val_loss - self.config.min_delta:
-                    self.best_val_loss = val_metrics["loss"]
-                    improved = True
-
-                if improved:
+                    self.best_val_loss = val_metrics["loss"]  # Track for reference
                     self.patience_counter = 0
                     self._save_checkpoint("best.pt")
                     self.logger.info("New best model saved!")