Is there a process to run a task daily
I had to do something similar recently. The extremely simple answer I came up with was to simply keep track of the last time the function was run with a db variable. 

So, in psudo code, I ended up doing something like this:

function hook_cron(){
  $now = new DateTime(date(DATE_ISO8601));
  $last_checked = new DateTime(variable_get('last_checkedvar', date(DATE_ISO8601, '0')));
  $diff = $now-&gt;diff( $last_checked );

  if ($diff-&gt;days &gt;= 1){
    //do your stuff
  }
}


Works well for me. And it also doesn't interfere with any of the other cron tasks I have running on my site.