Implementing breadcrumbs in Drupal can be difficult depending on your requirements. Drupal out of the box will generate a breadcrumb based off the menu structure, however, things start to get a little tricky when you want to modify breadcrumbs.
The module that I've had the most success with is the Path Breadcrumbs. This module offers great flexibility with an easy to use interface. Path Breadcrumbs' configuration can also be exported using Features which is another huge win.