diff --git a/nbs/src/core/core.ipynb b/nbs/src/core/core.ipynb
index 5748b84ff..373879472 100644
--- a/nbs/src/core/core.ipynb
+++ b/nbs/src/core/core.ipynb
@@ -838,9 +838,9 @@
     "#| exporti\n",
     "def _warn_df_constructor():\n",
     "    warnings.warn(\n",
-    "        \"The `df` argument of the StatsForecast constructor is deprecated \"\n",
-    "        \"and will be removed in a future version. \"\n",
-    "        \"Please pass `df` to the fit/forecast methods instead.\",\n",
+    "        \"The `df` argument of the StatsForecast constructor as well as reusing stored \"\n",
+    "        \"dfs from other methods is deprecated and will raise an error in a future version. \"\n",
+    "        \"Please provide the `df` argument to the corresponding method instead, e.g. fit/forecast.\",\n",
     "        category=DeprecationWarning,\n",
     "    )\n",
     "\n",
@@ -920,8 +920,7 @@
     "        self.freq = freq\n",
     "        self.n_jobs = n_jobs\n",
     "        self.fallback_model = fallback_model\n",
-    "        self.verbose = verbose \n",
-    "        self.n_jobs == 1\n",
+    "        self.verbose = verbose\n",
     "        if df is not None:\n",
     "            _warn_df_constructor()\n",
     "            self._prepare_fit(df=df, sort_df=sort_df)\n",
@@ -941,6 +940,8 @@
     "        sort_df: bool = True,\n",
     "    ) -> None:\n",
     "        if df is None:\n",
+    "            if not hasattr(self, 'ga'):\n",
+    "                raise ValueError('You must provide the `df` argument.')\n",
     "            _warn_df_constructor()\n",
     "            return\n",
     "        df = ensure_time_dtype(df, 'ds')\n",
@@ -1920,16 +1921,6 @@
     "assert all('the predictions will have the id as a column' in str(w.message) for w in issued_warnings)"
    ]
   },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "50d26dc0-5cfa-4328-a7ba-227940204b40",
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "import statsforecast"
-   ]
-  },
   {
    "cell_type": "code",
    "execution_count": null,
@@ -1937,7 +1928,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "statsforecast.config.id_as_index = False"
+    "sf_config.id_as_index = False"
    ]
   },
   {
diff --git a/statsforecast/core.py b/statsforecast/core.py
index 05a93aa40..d2feb224b 100644
--- a/statsforecast/core.py
+++ b/statsforecast/core.py
@@ -414,9 +414,9 @@ def _get_n_jobs(n_groups, n_jobs):
 # %% ../nbs/src/core/core.ipynb 27
 def _warn_df_constructor():
     warnings.warn(
-        "The `df` argument of the StatsForecast constructor is deprecated "
-        "and will be removed in a future version. "
-        "Please pass `df` to the fit/forecast methods instead.",
+        "The `df` argument of the StatsForecast constructor as well as reusing stored "
+        "dfs from other methods is deprecated and will raise an error in a future version. "
+        "Please provide the `df` argument to the corresponding method instead, e.g. fit/forecast.",
         category=DeprecationWarning,
     )
 
@@ -490,7 +490,6 @@ def __init__(
         self.n_jobs = n_jobs
         self.fallback_model = fallback_model
         self.verbose = verbose
-        self.n_jobs == 1
         if df is not None:
             _warn_df_constructor()
             self._prepare_fit(df=df, sort_df=sort_df)
@@ -512,6 +511,8 @@ def _prepare_fit(
         sort_df: bool = True,
     ) -> None:
         if df is None:
+            if not hasattr(self, "ga"):
+                raise ValueError("You must provide the `df` argument.")
             _warn_df_constructor()
             return
         df = ensure_time_dtype(df, "ds")