The objective of a phased approach to development is to break your site into individual components or features that can stand on their own. You start with a needs analysis, identifying the purpose of your site. For instance, assume your site will be a combination of an e-commerce site, library site, community site, and a product brochure site. You can proceed one of two ways.

1. Collect requirements and create a design for the entire system (all parts) and then develop each part one phase at a time

spiral methodology provides an iterative and progressive approach to defining the requirements and design of your site using prototyping. Once an operational prototype is reached, the development phase of production starts and you proceed using a waterfall approach. The spiral model suggests that a series of four steps be performed before coding begins. The following briefly describes the activities in each pass of the spiral, starting in the center of the spiral.

1. Determine your objectives, your alternatives for meeting your objectives, and any constraints that must be met.

While clearing caches is recommended in some situations, it is not recommended to clear caches while the site is busy.  However you can run drush command (drush cc) to get a list of your caches elements. Then you can use the list to build something like that.

Drupal is a free and open source CMS written in PHP and distributed under the GNU General Public License. Drupal stems from a project by a Dutch university student, Dries Buytaert. The goal of the project was to provide a mechanism for Buytaert and his friends to share news and events.

Buytaert turned Drupal into an open source project in 2001, and the community readily embraced the concept and has expanded on its humble beginnings, creating what is now one of the most powerful and featurerich CMS platforms on the web.