Dealing with hook_cron when configuration is required What's the best way in dealing with functions that require configuration in a hook_cron?

Example (pure fiction):

My hook_cron calls function_close_ticket, this function has various variable_gets all of which have defaults but those defaults may not be relevant to the users setup (they are however relevant to a default casetracker setup), especially if the user has customised casetracker a lot.

Would I be best leaving as is and letting hook_cron fire or wrapping the function inside in a call to get the state of a user configurable variable? Or is there some other way of dealing with this problem?
If you require configuration, then you shouldn't provide a default value using variable get (You provide an empty default value instead). If the no value is set, you should make a log using watchdog and exist without doing anything, since the conf was missing.

If you can provide a default settings that would make everything work, that would be a better option, since the user don't have to do any setup, be can if he wants to.

The checks should not really happen in cron, but in the function actually doing whatever needs to be done.