diff --git a/README.md b/README.md
index a9f06eb..b6ea11e 100644
--- a/README.md
+++ b/README.md
@@ -113,8 +113,12 @@ process selection options:
   - Example: `--process-levels=L1,L2`.`
   - A level does not imply other levels, so each desired level must be specified explicitly.
     For example, L2 does **not** include L1 automatically.
-- `--experimental`: Enables tests for experimental processes.
-  By default experimental processes will be skipped.
+
+If neither `--processes` nor `--process-levels` are specified, all processes are considered.
+If both are specified, the union of both will be considered.
+
+- `--experimental`: By default, experimental processes (or experimental process tests) are ignored.
+  Enabling this option will consider experimental processes and tests.
 
 
 ### Runner for individual process testing
diff --git a/src/openeo_test_suite/lib/pytest_plugin.py b/src/openeo_test_suite/lib/pytest_plugin.py
index a02f861..0a3f5dd 100644
--- a/src/openeo_test_suite/lib/pytest_plugin.py
+++ b/src/openeo_test_suite/lib/pytest_plugin.py
@@ -25,13 +25,17 @@ def pytest_addoption(parser):
         "--process-levels",
         action="store",
         default="",
-        help="The openEO process profiles you want to test against, e.g. 'L1,L2,L2A'. Mutually exclusive with --processes.",
+        help="openEO process selection: "
+        "the openEO process profiles/levels you want to test against, e.g. 'L1,L2,L2A'. "
+        "Can be used in combination with `--processes`, in which case the union of both selections will be taken. ",
     )
     parser.addoption(
         "--processes",
         action="store",
         default="",
-        help="The openEO processes you want to test against, e.g. 'apply,reduce_dimension'. Mutually exclusive with --process-levels.",
+        help="openEO process selection: "
+        "the openEO processes you want to test against, e.g. 'apply,reduce_dimension'. "
+        "Can be used in combination with `--process-levels`, in which case the union of both selections will be taken.",
     )
 
     parser.addoption(
@@ -39,7 +43,9 @@ def pytest_addoption(parser):
         type=bool,
         action=argparse.BooleanOptionalAction,
         default=False,
-        help="Run tests for experimental functionality or not. By default the tests will be skipped.",
+        help="openEO process selection: "
+        "toggle to consider experimental processes (and experimental tests) in the test selection procedure. "
+        "By default, experimental processes are ignored.",
     )
 
     parser.addoption(