diff --git a/src/Configuration/RectorConfigBuilder.php b/src/Configuration/RectorConfigBuilder.php
index 5d96678a1f..8dff9de935 100644
--- a/src/Configuration/RectorConfigBuilder.php
+++ b/src/Configuration/RectorConfigBuilder.php
@@ -158,9 +158,6 @@ final class RectorConfigBuilder
 
     private ?string $editorUrl = null;
 
-    /**
-     * @api soon to be used
-     */
     private ?bool $isWithPhpSetsUsed = null;
 
     private ?bool $isWithPhpLevelUsed = null;
@@ -533,6 +530,14 @@ public function withPhpSets(
         bool $php53 = false,
         bool $php84 = false, // place on later as BC break when used in php 7.x without named arg
     ): self {
+        if ($this->isWithPhpSetsUsed === true) {
+            throw new InvalidConfigurationException(sprintf(
+                'Method "%s()" can be called only once. It always includes all previous sets UP TO the defined version.%sThe best practise is to call it once with no argument. That way it will pick up PHP version from composer.json and your project will always stay up to date.',
+                __METHOD__,
+                PHP_EOL
+            ));
+        }
+
         $this->isWithPhpSetsUsed = true;
 
         $pickedArguments = array_filter(func_get_args());