There are advantages making a process daemonized, as it it detached from the terminal. But the same thing also can be achieved by cron job as well. [ Kindly correct me if not ]
What is the best requirement with which i can differentiate the scenarios when to use cronjob or daemon process?
In general, if your task needs to run more than a few times per hour (maybe <10 minutes) you probably want to run a daemon.
A daemon which is always running, has the following benefits:
In general, robustness favours "cron", and performance favours a daemon. But there is a lot of overlap (where either would be ok) and counter-examples. It depends on your exact scenario.