diff --git a/src/Checks/FileAccessibilityAndValidationCheck.php b/src/Checks/FileAccessibilityAndValidationCheck.php
index abff14b..6bae00c 100644
--- a/src/Checks/FileAccessibilityAndValidationCheck.php
+++ b/src/Checks/FileAccessibilityAndValidationCheck.php
@@ -80,7 +80,7 @@ class FileAccessibilityAndValidationCheck implements EnvironmentCheck
     {
         $this->path = $path;
         $this->fileTypeValidateFunc = ($fileTypeValidateFunc)? $fileTypeValidateFunc : 'noVidation';
-        $this->checkType = ($checkType) ? $checkType : self::CHECK_SINGLE;
+        $this->checkType = ($checkType) ? $checkType : FileAccessibilityAndValidationCheck::CHECK_SINGLE;
     }
 
     /**
@@ -109,7 +109,9 @@ class FileAccessibilityAndValidationCheck implements EnvironmentCheck
                 }
 
                 // If at least one file was valid, count as passed
-                if ($this->checkType == self::CHECK_SINGLE && count($invalidFiles ?? []) < count($files ?? [])) {
+                if ($this->checkType == FileAccessibilityAndValidationCheck::CHECK_SINGLE
+                    && count($invalidFiles ?? []) < count($files ?? [])
+                ) {
                     $validFileList = PHP_EOL;
                     foreach ($validFiles as $vf) {
                         $validFileList .= $vf . PHP_EOL;
diff --git a/src/Checks/FileAgeCheck.php b/src/Checks/FileAgeCheck.php
index ff7dea3..5cc8050 100644
--- a/src/Checks/FileAgeCheck.php
+++ b/src/Checks/FileAgeCheck.php
@@ -85,7 +85,7 @@ class FileAgeCheck implements EnvironmentCheck
         $this->path = $path;
         $this->relativeAge = $relativeAge;
         $this->checkFn = $checkFn;
-        $this->checkType = ($checkType) ? $checkType : self::CHECK_SINGLE;
+        $this->checkType = ($checkType) ? $checkType : FileAgeCheck::CHECK_SINGLE;
         $this->compareOperand = $compareOperand;
     }
 
@@ -110,7 +110,7 @@ class FileAgeCheck implements EnvironmentCheck
                     $validFiles[] = $file;
                 } else {
                     $invalidFiles[] = $file;
-                    if ($this->checkType == self::CHECK_ALL) {
+                    if ($this->checkType == FileAgeCheck::CHECK_ALL) {
                         return [
                             EnvironmentCheck::ERROR,
                             sprintf(
@@ -127,7 +127,7 @@ class FileAgeCheck implements EnvironmentCheck
         }
 
         // If at least one file was valid, count as passed
-        if ($this->checkType == self::CHECK_SINGLE && count($invalidFiles ?? []) < count($files ?? [])) {
+        if ($this->checkType == FileAgeCheck::CHECK_SINGLE && count($invalidFiles ?? []) < count($files ?? [])) {
             return [EnvironmentCheck::OK, ''];
         }
         if (count($invalidFiles ?? []) == 0) {
diff --git a/src/EnvironmentCheckSuite.php b/src/EnvironmentCheckSuite.php
index 3950126..c17f901 100644
--- a/src/EnvironmentCheckSuite.php
+++ b/src/EnvironmentCheckSuite.php
@@ -74,7 +74,8 @@ class EnvironmentCheckSuite
     public function __construct($suiteName)
     {
         if (empty($this->config()->registered_suites[$suiteName])) {
-            // Not registered via config system, but it still may be configured later via self::register.
+            // Not registered via config system, but it still may be configured later
+            // via EnvironmentCheckSuite::register.
             return;
         }
 
@@ -181,10 +182,10 @@ class EnvironmentCheckSuite
      */
     public static function inst($name)
     {
-        if (!isset(self::$instances[$name])) {
-            self::$instances[$name] = new EnvironmentCheckSuite($name);
+        if (!isset(EnvironmentCheckSuite::$instances[$name])) {
+            EnvironmentCheckSuite::$instances[$name] = new EnvironmentCheckSuite($name);
         }
-        return self::$instances[$name];
+        return EnvironmentCheckSuite::$instances[$name];
     }
 
     /**
@@ -201,7 +202,7 @@ class EnvironmentCheckSuite
         }
 
         foreach ($names as $name) {
-            self::inst($name)->push($check, $title);
+            EnvironmentCheckSuite::inst($name)->push($check, $title);
         }
     }
 
@@ -210,6 +211,6 @@ class EnvironmentCheckSuite
      */
     public static function reset()
     {
-        self::$instances = [];
+        EnvironmentCheckSuite::$instances = [];
     }
 }