diff --git a/.github/actions/install-deps/action.yml b/.github/actions/install-deps/action.yml
new file mode 100644
index 00000000..fadc7f4a
--- /dev/null
+++ b/.github/actions/install-deps/action.yml
@@ -0,0 +1,43 @@
+name: Install Dependencies
+description: Install package dependencies using uv
+
+inputs:
+  options:
+    # We can't directly provide the empty string for no options because it would be mapped to the
+    # default value thanks to github's weird logic (https://github.com/actions/toolkit/issues/940)
+    description: 'Package options to install (space-separated, e.g., "full"). Use "none" for no options.'
+    required: false
+    default: 'full'
+  groups:
+    description: 'Dependency groups to install (space-separated, e.g., "test doc")'
+    required: false
+    default: ''
+
+runs:
+  using: composite
+  steps:
+    - name: Install dependencies (options=[${{ inputs.options }}], groups=[${{ inputs.groups }}])
+      shell: bash
+      run: |
+        # Map "none" to the empty string
+        options_input="${{ inputs.options }}"
+        if [ "$options_input" = "none" ]; then
+          options_input=""
+        fi
+
+        # Build the install command
+        cmd="uv pip install -e"
+
+        # Convert space-separated options to comma-separated for brackets
+        # E.g. "abc def" => '.[abc,def]'
+        options=$(echo "$options_input" | tr ' ' ',')
+        cmd="$cmd '.[$options]'"
+
+        # Add groups
+        for group in ${{ inputs.groups }}; do
+          cmd="$cmd --group $group"
+        done
+
+        # Print and execute the command
+        echo $cmd
+        eval $cmd
diff --git a/.github/workflows/build-deploy-docs.yml b/.github/workflows/build-deploy-docs.yml
index 891e42f5..337b143b 100644
--- a/.github/workflows/build-deploy-docs.yml
+++ b/.github/workflows/build-deploy-docs.yml
@@ -8,7 +8,6 @@ on:
 
 env:
   UV_NO_SYNC: 1
-  PYTHON_VERSION: '3.14'
 
 jobs:
   build-deploy-doc:
@@ -24,10 +23,11 @@ jobs:
       - name: Set up uv
         uses: astral-sh/setup-uv@v5
         with:
-          python-version: ${{ env.PYTHON_VERSION }}
+          python-version: '3.14'
 
-      - name: Install dependencies (default with full options & doc)
-        run: uv pip install --python-version=${{ env.PYTHON_VERSION }} -e '.[full]' --group doc
+      - uses: ./.github/actions/install-deps
+        with:
+          groups: doc
 
       - name: Determine deployment folder
         id: deploy_folder
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 282ac671..02cc877d 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -4,9 +4,6 @@ on:
   release:
     types: [published]
 
-env:
-  PYTHON_VERSION: 3.14
-
 jobs:
   pypi-publish:
     name: Publish to PyPI
@@ -22,7 +19,7 @@ jobs:
       - name: Set up uv
         uses: astral-sh/setup-uv@v5
         with:
-          python-version: ${{ env.PYTHON_VERSION }}
+          python-version: '3.14'
 
       - name: Build
         run: uv build
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index ee628ee3..6b604fa3 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -8,72 +8,52 @@ on:
 
 env:
   UV_NO_SYNC: 1
-  PYTHON_VERSION: 3.14
 
 jobs:
-  tests-full-install:
-    name: Run tests with full install
-    runs-on: ${{ matrix.os }}
+  tests:
+    # Default config: py3.14, ubuntu-latest, float32, full options.
+    # The idea is to make each of those params vary one by one, to limit the number of tests to run.
+    name: Run tests (py${{ matrix.python-version || '3.14' }}, ${{ matrix.os || 'ubuntu-latest' }}, ${{ matrix.dtype || 'float32' }}, ${{ matrix.options || 'full' }})
+    runs-on: ${{ matrix.os || 'ubuntu-latest' }}
     strategy:
-      fail-fast: false  # Ensure matrix jobs keep running even if one fails
+      fail-fast: false
       matrix:
-        python-version: ['3.10', '3.11', '3.12', '3.13', '3.14']
-        os: [ubuntu-latest, macOS-latest, windows-latest]
+        include:
+          # Python version variations
+          - python-version: '3.10'
+          - python-version: '3.11'
+          - python-version: '3.12'
+          - python-version: '3.13'
+          - python-version: '3.14'  # To actually run the default config
+          # OS variations
+          - os: macOS-latest
+          - os: windows-latest
+          # dtype variations
+          - dtype: float64
+          # Installation options variations
+          - options: 'none'
 
     steps:
-      - uses: actions/checkout@v4
-      - name: Set up uv
-        uses: astral-sh/setup-uv@v5
-        with:
-          python-version: ${{ matrix.python-version }}
-      - name: Install default (with full options) and test dependencies
-        run: uv pip install --python-version=${{ matrix.python-version }} -e '.[full]' --group test
-      - name: Run unit and doc tests with coverage report
-        run: uv run pytest -W error tests/unit tests/doc --cov=src --cov-report=xml
-      - name: Upload results to Codecov
-        uses: codecov/codecov-action@v4
-        with:
-          token: ${{ secrets.CODECOV_TOKEN }}
+      - name: Checkout repository
+        uses: actions/checkout@v4
 
-  tests-default-install:
-    name: Run (most) tests with default install
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
       - name: Set up uv
         uses: astral-sh/setup-uv@v5
         with:
-          python-version: ${{ env.PYTHON_VERSION }}
-      - name: Install default (without any option) and test dependencies
-        run: uv pip install --python-version=${{ env.PYTHON_VERSION }} -e . --group test
-      - name: Run unit and doc tests with coverage report
-        run: |
-          uv run pytest -W error tests/unit tests/doc \
-          --ignore tests/unit/aggregation/test_cagrad.py \
-          --ignore tests/unit/aggregation/test_nash_mtl.py \
-          --ignore tests/doc/test_aggregation.py \
-          --cov=src --cov-report=xml
-      - name: Upload results to Codecov
-        uses: codecov/codecov-action@v4
-        with:
-          token: ${{ secrets.CODECOV_TOKEN }}
+          python-version: ${{ matrix.python-version || '3.14' }}
 
-  tests-float64:
-    name: Run tests on float64 dtype
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
-      - name: Set up uv
-        uses: astral-sh/setup-uv@v5
+      - uses: ./.github/actions/install-deps
         with:
-          python-version: ${{ env.PYTHON_VERSION }}
-      - name: Install default (with full options) and test dependencies
-        run: uv pip install --python-version=${{ env.PYTHON_VERSION }} -e '.[full]' --group test
-      - name: Run unit and doc tests with coverage report
+          options: ${{ matrix.options || 'full' }}
+          groups: test
+
+      - name: Run tests
         run: uv run pytest -W error tests/unit tests/doc --cov=src --cov-report=xml
         env:
-          PYTEST_TORCH_DTYPE: float64
-      - name: Upload results to Codecov
+          PYTEST_TORCH_DTYPE: ${{ matrix.dtype || 'float32' }}
+
+      - &upload-codecov
+        name: Upload results to Codecov
         uses: codecov/codecov-action@v4
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
@@ -88,10 +68,11 @@ jobs:
       - name: Set up uv
         uses: astral-sh/setup-uv@v5
         with:
-          python-version: ${{ env.PYTHON_VERSION }}
+          python-version: '3.14'
 
-      - name: Install dependencies (default with full options & doc)
-        run: uv pip install --python-version=${{ env.PYTHON_VERSION }} -e '.[full]' --group doc
+      - uses: ./.github/actions/install-deps
+        with:
+          groups: doc
 
       - name: Build Documentation
         working-directory: docs
@@ -101,16 +82,17 @@ jobs:
     name: Run mypy
     runs-on: ubuntu-latest
     steps:
-    - name: Checkout repository
-      uses: actions/checkout@v4
+      - name: Checkout repository
+        uses: actions/checkout@v4
 
-    - name: Set up uv
-      uses: astral-sh/setup-uv@v5
-      with:
-        python-version: ${{ env.PYTHON_VERSION }}
+      - name: Set up uv
+        uses: astral-sh/setup-uv@v5
+        with:
+          python-version: '3.14'
 
-    - name: Install dependencies (default with full options & check)
-      run: uv pip install --python-version=${{ env.PYTHON_VERSION }} -e '.[full]' --group check
+      - uses: ./.github/actions/install-deps
+        with:
+          groups: check
 
-    - name: Run mypy
-      run: uv run mypy src/torchjd
+      - name: Run mypy
+        run: uv run mypy src/torchjd
diff --git a/tests/unit/aggregation/test_cagrad.py b/tests/unit/aggregation/test_cagrad.py
index e604c087..e77cb729 100644
--- a/tests/unit/aggregation/test_cagrad.py
+++ b/tests/unit/aggregation/test_cagrad.py
@@ -5,7 +5,12 @@
 from utils.contexts import ExceptionContext
 from utils.tensors import ones_
 
-from torchjd.aggregation import CAGrad
+try:
+    from torchjd.aggregation import CAGrad
+except ImportError:
+    import pytest
+
+    pytest.skip("CAGrad dependencies not installed", allow_module_level=True)
 
 from ._asserts import assert_expected_structure, assert_non_conflicting, assert_non_differentiable
 from ._inputs import scaled_matrices, typical_matrices
diff --git a/tests/unit/aggregation/test_nash_mtl.py b/tests/unit/aggregation/test_nash_mtl.py
index ce343e5d..e4a47642 100644
--- a/tests/unit/aggregation/test_nash_mtl.py
+++ b/tests/unit/aggregation/test_nash_mtl.py
@@ -3,7 +3,12 @@
 from torch.testing import assert_close
 from utils.tensors import ones_, randn_
 
-from torchjd.aggregation import NashMTL
+try:
+    from torchjd.aggregation import NashMTL
+except ImportError:
+    import pytest
+
+    pytest.skip("NashMTL dependencies not installed", allow_module_level=True)
 
 from ._asserts import assert_expected_structure, assert_non_differentiable
 from ._inputs import nash_mtl_matrices