In the full W3 Total Cache FAQ, I found this question and answer:
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How fast will the cache be updated?
Items expire from the cache at a rate that you specify. As far as how fast changes appear to your visitors, they appear instantly in most cases and if you're an administrator who's logged in they will always be immediately visible.
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When looking at the Page Cache settings, I find the advanced "Garbage collection interval" setting, with this description:
"If caching to disk, specify how frequently expired cache data is removed. For busy sites, a lower value is best."
The default value is 3600 and I haven't changed it.
I'm using "disk enhanced" caching on my WordPress based site, which has ONLY static pages and no blog posts. I understand the "Garbage collection interval" setting to refer to the time interval that W3 Total Cache will delete "old" or "stale" cached content. However, I'm not finding any settings which actually control the expiration time of the content being cached.
So, do I control the expiration of the content being cached through Expires directives I specify in a htaccess file should I be able to control the expiration of the content being cached through W3 Total Cache itself?