diff --git a/.gitignore b/.gitignore
index 293ef8fe..805b0ccd 100644
--- a/.gitignore
+++ b/.gitignore
@@ -24,3 +24,4 @@ nrnivmodl.log
 .ruff_cache
 .pytest_cache
 *.btr
+*.whl
diff --git a/bluecellulab/cell/core.py b/bluecellulab/cell/core.py
index af5b1c80..194c0e50 100644
--- a/bluecellulab/cell/core.py
+++ b/bluecellulab/cell/core.py
@@ -39,6 +39,7 @@
 from bluecellulab.circuit.node_id import CellId
 from bluecellulab.circuit.simulation_access import get_synapse_replay_spikes
 from bluecellulab.exceptions import BluecellulabError
+from bluecellulab.importer import load_hoc_and_mod_files
 from bluecellulab.neuron_interpreter import eval_neuron
 from bluecellulab.rngsettings import RNGSettings
 from bluecellulab.stimuli import SynapseReplay
@@ -54,6 +55,7 @@ class Cell(InjectableMixin, PlottableMixin):
 
     last_id = 0
 
+    @load_hoc_and_mod_files
     def __init__(self,
                  template_path: str | Path,
                  morphology_path: str | Path,
@@ -134,7 +136,7 @@ def __init__(self,
         self.secname_to_psection: dict[str, psection.PSection] = {}
 
         self.emodel_properties = emodel_properties
-        if template_format in ['v6']:
+        if template_format == 'v6':
             if self.emodel_properties is None:
                 raise BluecellulabError('EmodelProperties must be provided for v6 template')
             self.hypamp: float | None = self.emodel_properties.holding_current
diff --git a/bluecellulab/importer.py b/bluecellulab/importer.py
index 18a65d51..2f76a61c 100644
--- a/bluecellulab/importer.py
+++ b/bluecellulab/importer.py
@@ -21,6 +21,7 @@
 import neuron
 
 from bluecellulab.exceptions import BluecellulabError
+from bluecellulab.utils import run_once
 
 
 logger = logging.getLogger(__name__)
@@ -71,6 +72,18 @@ def print_header(neuron: ModuleType, mod_lib_path: str) -> None:
     logger.info(f"Mod lib: {mod_lib_path}")
 
 
-mod_lib_paths = import_mod_lib(neuron)
-import_neurodamus(neuron)
-print_header(neuron, mod_lib_paths)
+@run_once
+def _load_hoc_and_mod_files() -> None:
+    """Import hoc and mod files."""
+    logger.info("Loading the mod files.")
+    mod_lib_paths = import_mod_lib(neuron)
+    logger.info("Loading the hoc files.")
+    import_neurodamus(neuron)
+    print_header(neuron, mod_lib_paths)
+
+
+def load_hoc_and_mod_files(func):
+    def wrapper(*args, **kwargs):
+        _load_hoc_and_mod_files()
+        return func(*args, **kwargs)
+    return wrapper
diff --git a/bluecellulab/rngsettings.py b/bluecellulab/rngsettings.py
index ccfb90b1..fe4925b8 100644
--- a/bluecellulab/rngsettings.py
+++ b/bluecellulab/rngsettings.py
@@ -21,6 +21,7 @@
 from bluecellulab import Singleton
 from bluecellulab.circuit.circuit_access import CircuitAccess
 from bluecellulab.exceptions import UndefinedRNGException
+from bluecellulab.importer import load_hoc_and_mod_files
 
 logger = logging.getLogger(__name__)
 
@@ -28,6 +29,7 @@
 class RNGSettings(metaclass=Singleton):
     """Class that represents RNG settings in bluecellulab."""
 
+    @load_hoc_and_mod_files
     def __init__(
             self,
             mode: Optional[str] = None,
@@ -41,7 +43,6 @@ def __init__(
         circuit: circuit access object, if present seeds are read from simulation
         base_seed: base seed for entire sim, overrides config value
         """
-
         self._mode = ""
         if mode is None:
             if circuit_access is not None:
diff --git a/bluecellulab/ssim.py b/bluecellulab/ssim.py
index 25fd0054..8a51342b 100644
--- a/bluecellulab/ssim.py
+++ b/bluecellulab/ssim.py
@@ -39,6 +39,7 @@
 from bluecellulab.circuit.format import determine_circuit_format, CircuitFormat
 from bluecellulab.circuit.node_id import create_cell_id, create_cell_ids
 from bluecellulab.circuit.simulation_access import BluepySimulationAccess, SimulationAccess, SonataSimulationAccess, _sample_array
+from bluecellulab.importer import load_hoc_and_mod_files
 from bluecellulab.stimuli import Noise, OrnsteinUhlenbeck, RelativeOrnsteinUhlenbeck, RelativeShotNoise, ShotNoise
 import bluecellulab.stimuli as stimuli
 from bluecellulab.exceptions import BluecellulabError
@@ -54,6 +55,7 @@
 class SSim:
     """Class that loads a circuit simulation to do cell simulations."""
 
+    @load_hoc_and_mod_files
     def __init__(
         self,
         simulation_config: str | Path | SimulationConfig,
diff --git a/bluecellulab/utils.py b/bluecellulab/utils.py
new file mode 100644
index 00000000..00cec6fd
--- /dev/null
+++ b/bluecellulab/utils.py
@@ -0,0 +1,11 @@
+"""Utility functions."""
+
+
+def run_once(func):
+    """A decorator to ensure a function is only called once."""
+    def wrapper(*args, **kwargs):
+        if not wrapper.has_run:
+            wrapper.has_run = True
+            return func(*args, **kwargs)
+    wrapper.has_run = False
+    return wrapper
diff --git a/tests/test_importer.py b/tests/test_importer.py
index 21f88d6a..c9da6142 100644
--- a/tests/test_importer.py
+++ b/tests/test_importer.py
@@ -74,3 +74,18 @@ def test_print_header(caplog):
 
     assert "Imported NEURON from: /path/to/neuron" in caplog.text
     assert "Mod lib: /path/to/mod_lib" in caplog.text
+
+
+def test_print_header_with_decorator(caplog):
+    """Ensure the decorator loading hoc and mod files work as expected."""
+    with caplog.at_level(logging.INFO):
+        @importer.load_hoc_and_mod_files
+        def x():
+            pass
+
+        x()  # call 3 times to ensure the decorator is called only once
+        x()
+        x()
+
+    assert caplog.text.count("Loading the mod files.") == 1
+    assert caplog.text.count("Loading the hoc files.") == 1
diff --git a/tests/test_neuron_interpreter.py b/tests/test_neuron_interpreter.py
index a5a21407..5fd3872d 100644
--- a/tests/test_neuron_interpreter.py
+++ b/tests/test_neuron_interpreter.py
@@ -8,6 +8,7 @@
 
 import bluecellulab
 from bluecellulab.exceptions import NeuronEvalError
+from bluecellulab.importer import _load_hoc_and_mod_files
 from bluecellulab.neuron_interpreter import eval_neuron
 
 script_dir = os.path.dirname(__file__)
@@ -15,6 +16,7 @@
 
 def test_eval_neuron():
     """Unit test for the eval_neuron function."""
+    _load_hoc_and_mod_files()
     eval_neuron("neuron.h.nil", neuron=neuron)
     with raises(NeuronEvalError):
         eval_neuron("1+1")
diff --git a/tests/test_simulation/test_neuron_globals.py b/tests/test_simulation/test_neuron_globals.py
index 2b90ca1c..a9310faf 100644
--- a/tests/test_simulation/test_neuron_globals.py
+++ b/tests/test_simulation/test_neuron_globals.py
@@ -4,10 +4,12 @@
 import neuron
 
 from bluecellulab.circuit.config.sections import ConditionEntry, Conditions, MechanismConditions
+from bluecellulab.importer import _load_hoc_and_mod_files
 from bluecellulab.simulation.neuron_globals import set_global_condition_parameters, set_init_depleted_values, set_minis_single_vesicle_values, set_tstop_value
 
 
 def test_set_tstop_value():
+    _load_hoc_and_mod_files()  # this is a run_once function
     set_tstop_value(100.0)
     assert neuron.h.tstop == 100.0
 
diff --git a/tests/test_utils.py b/tests/test_utils.py
new file mode 100644
index 00000000..d3dc58ec
--- /dev/null
+++ b/tests/test_utils.py
@@ -0,0 +1,26 @@
+from bluecellulab.utils import run_once
+
+
+# Decorated function for testing
+@run_once
+def increment_counter(counter):
+    counter[0] += 1
+    return "Executed"
+
+
+def test_run_once_execution():
+    """Test that the decorated function runs only once."""
+    counter = [0]  # Using a list for mutability
+
+    assert increment_counter(counter) == "Executed"
+    increment_counter(counter)
+    assert counter[0] == 1
+
+    # Called 3 times but increased once
+    increment_counter(counter)
+    increment_counter(counter)
+    increment_counter(counter)
+
+    assert counter[0] == 1
+
+    assert increment_counter(counter) is None