What is the default behavior of the Drupal 7 cache? I can't find any specific documentation explaining how the default caching mechanism in Drupal 7 works and when does it clear caches automatically. From my own testing, I can state the following:


Cache is cleared when any content is added
Cache is cleared when any content is updated
Cache is NOT cleared when content is deleted!!! (Check my comment below for update).


Where can I find documentation to approve the above and also learn a little more about this topic? Any other cases where cache is auto cleared?

Details: the above results are based on turning on both "Cache pages for anonymous users" and "Cache blocks" and setting "Minimum cache lifetime" and "Expiration of cached pages" to none.
To find out all events when page and block cache is cleared - you can search through all modules for using of cache_clear_all() function.

Here is brief list of such events in Drupal core.


Any content is created or updated (nodes, taxonomy terms, comments, etc)
Content permissions are updated. 
Block is created or updated.
Vocabulary created, edited or deleted.
Any settings form in admin back-end is submitted (those forms that use system_settings_form()).
User account is created, updated or canceled.


As you see page and block cache is not cleared automatically when any content is deleted.