Hello KT,
Thank you for reaching out and I am happy to help!
W3 Total Cache does not auto-purge cache unless the post/article is published/updated or any other change on the website that triggers the Perofmrnace>Page Cache>Purge Policy settings. In other words, if the cache is not purged, the cache will remain the same.
You can entirely disable those options in Perofmrnace>Page Cache>Purge Policy settings if you want to purge the cache manually or you do not wish to purge the cache at all.
Thanks!