diff --git a/noxfile.py b/noxfile.py
index c7c0648c..f0bc0e5b 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -3,17 +3,20 @@
 import nox
 
 os.environ.update({"PDM_IGNORE_SAVED_PYTHON": "1"})
+nox.options.reuse_existing_virtualenvs = 1
 
 
 @nox.session
 def validate_code(session):
-    session.run_always("pdm", "install", "-G", "dev", "--no-self", external=True)
+    session.run_always(
+        "pdm", "sync", "--clean", "-G", "dev", "--no-self", external=True
+    )
     session.run("pdm", "validate_code", external=True)
 
 
 @nox.session
 def test_without_fft_and_pythran(session):
-    command = "pdm install -G dev -G test -G mpi --no-self"
+    command = "pdm sync --clean -G dev -G test -G mpi --no-self"
     session.run_always(*command.split(), external=True)
     session.install(
         ".", "--config-settings=setup-args=-Dtransonic-backend=python", "--no-deps"
@@ -31,7 +34,7 @@ def test_with_fft_and_pythran(session):
     # first install fluidfft without Pythran compilation
     session.install("fluidfft", env={"FLUIDFFT_TRANSONIC_BACKEND": "python"})
 
-    command = "pdm install -G dev -G test -G fft -G mpi --no-self"
+    command = "pdm sync --clean -G dev -G test -G fft -G mpi --no-self"
     session.run_always(*command.split(), external=True)
     session.install(".", "--no-deps", "-C", "setup-args=-Dnative=true")