Note that this article applies primarily to Drupal 6. When developing features or other modules, I often find myself making changes to the module dependencies or other aspects after my module has first been moved to the staging site. I use hook_update_N() for that. Here's how.
Features normally don't do anything to the database, so typically we won't have an implementation of hook_install(), but we can still do stuff like add URL aliases using the install hook.