In most cases you shouldn't have to worry about leaving it plugged in. Only in old/unhealthy batteries will leaving Automatic plugged in cause a battery to be drained.
If you're experiencing a long crank, the clock resetting or radio resetting occasionally, a car alarm going off randomly, your handsfree bluetooth link having intermittent issues, those might be signs of an old/unhealthy battery. In those situations, I would recommend unplugging the Automatic link.
If you're unsure about your battery's health, I recommend unplugging your Link while you're gone, then plugging it back in before you start driving again.