Boost caching: what refreshes it and how?

A normal (node) page triggers the Drupal-integrated Boost cache to expire and replace the page whenever you edit it. Editing a view unfortunately does not have such triggers. In this case the views are attached to a node, so simply resaving the node rebuilds the cache.

In most cases the view itself will not be modified, rather, you will add or edit a node associated with a view which also refreshes the cache for that views pages. (Note this takes a bit of processing to look up, and i don't think it will apply for blocks.)

Finally, deleting a cache file manually is an easy and perfectly acceptable way to make the associated page page fresh immediately; a new cache will be produced the first time the page is hit by a user or by Boost's own crawler.

Cache files live within the web root (drupal), a path on your server might be: public_html/example-v2/drupal/cache/normal/www.example.com/