diff --git a/controller/iconcontroller.php b/controller/iconcontroller.php
index 8507dc19..6d821a17 100644
--- a/controller/iconcontroller.php
+++ b/controller/iconcontroller.php
@@ -28,6 +28,7 @@ class IconController extends ApiController {
 	private $credentialService;
 	private $am;
 	private $urlGenerator;
+	const ICON_CACHE_OFFSET = 2592000;  // 3600 * 24 * 30
 
 	public function __construct($AppName,
 	                            IRequest $request,
@@ -126,15 +127,14 @@ class IconController extends ApiController {
 		}
 
 
-		$offset = 3600 * 24 * 30;
 		$contentType = 'image/png';
 		$response = new DataDownloadResponse($data, 'icon', $contentType);
 
 		$response->addHeader('Content-Type', $contentType);
 		$response->addHeader('Content-Length:', mb_strlen($data));
-		$response->addHeader('Expires: ', gmdate("D, d M Y H:i:s", time() + $offset) . " GMT");
+		$response->addHeader('Expires: ', gmdate("D, d M Y H:i:s", time() + self::ICON_CACHE_OFFSET) . " GMT");
 		$response->setETag($base64Url);
-		$response->cacheFor($offset);
+		$response->cacheFor(self::ICON_CACHE_OFFSET);
 
 		return $response;
 	}
@@ -167,10 +167,9 @@ class IconController extends ApiController {
 			}
 		}
 
-		$offset = 3600 * 24 * 30;
 		$response = new JSONResponse($icons);
-		$response->addHeader('Expires: ', gmdate("D, d M Y H:i:s", time() + $offset) . " GMT");
-		$response->cacheFor($offset);
+		$response->addHeader('Expires: ', gmdate("D, d M Y H:i:s", time() + self::ICON_CACHE_OFFSET) . " GMT");
+		$response->cacheFor(self::ICON_CACHE_OFFSET);
 
 		return $response;
 	}