- Reduce default cache constant that was removed in magento#9841 (rem…

…oved as currency wasn't included in cache key, now is added via this plugin https://github.com/VortexCommerce/magento2/blob/23d76ed074d7d5e465cbed782a2831abe192de96/app/code/Magento/Catalog/Block/Category/Plugin/PriceBoxTags.php#L68)

- Increase default cache time to 1 day (86400) this is more that acceptable as the cache key includes the current date so will not load for a new day which could have a new price rule, special price etc...

lib/internal/Magento/Framework/Pricing/Render/PriceBox.php

@@ -21,7 +21,7 @@
 class PriceBox extends Template implements PriceBoxRenderInterface, IdentityInterface
 {
     /** Default block lifetime */
-    const DEFAULT_LIFETIME = 3600;
+    const DEFAULT_LIFETIME = 86400;
 
     /**
      * @var SaleableInterface
@@ -86,7 +86,7 @@ public function getCacheKey()
      */
     protected function getCacheLifetime()
     {
-        return parent::hasCacheLifetime() ? parent::getCacheLifetime() : null;
+        return parent::hasCacheLifetime() ? parent::getCacheLifetime() : self::DEFAULT_LIFETIME;
     }
 
     /**