Do your css or js files change twice a day?
There should be absolutely no need to do that, unless you change the css or js code twice a day.
If you really need to programatically purge the cache, make sure you also purge any server or cache plugins after you purge fvm.
if (function_exists('fvm_purge_all')) {
fvm_purge_all(); # deletes fvm transients and deletes js / css cache files
}
There’s another function that tries to purge third party cache plugins, but it may or may not work on your server. I would advise you to use your own cache system method to clear the cache.
if (function_exists('fastvelocity_purge_others')) {
fastvelocity_purge_others(); # tries to purge some third party caches
}