diff --git a/src/batdetect2/train/checkpoints.py b/src/batdetect2/train/checkpoints.py
index 92db951..e93c7ca 100644
--- a/src/batdetect2/train/checkpoints.py
+++ b/src/batdetect2/train/checkpoints.py
@@ -1,4 +1,5 @@
 from pathlib import Path
+from typing import Literal
 
 from lightning.pytorch.callbacks import Callback, ModelCheckpoint
 
@@ -14,11 +15,12 @@ DEFAULT_CHECKPOINT_DIR: Path = Path("outputs") / "checkpoints"
 
 class CheckpointConfig(BaseConfig):
     checkpoint_dir: Path = DEFAULT_CHECKPOINT_DIR
-    monitor: str = "classification/mean_average_precision"
+    monitor: str | None = None
     mode: str = "max"
     save_top_k: int = 1
     filename: str | None = None
-    save_last: bool = False
+    save_last: bool | Literal["link"] = "link"
+    every_n_epochs: int | None = 1
 
 
 def build_checkpoint_callback(
@@ -38,6 +40,8 @@ def build_checkpoint_callback(
     if run_name is not None:
         checkpoint_dir = checkpoint_dir / run_name
 
+    checkpoint_dir.mkdir(parents=True, exist_ok=True)
+
     return ModelCheckpoint(
         dirpath=str(checkpoint_dir),
         save_top_k=config.save_top_k,
@@ -45,4 +49,5 @@ def build_checkpoint_callback(
         mode=config.mode,
         filename=config.filename,
         save_last=config.save_last,
+        every_n_epochs=config.every_n_epochs,
     )