I've had this model 330 for a few years now.  When I wear it, I often forget that I have it on (it's that comfortable).  When it was new, it would hold a charge up to 3 days with occasional use.  I find myself putting it on the charger much more often lately, usually every night.  Speaking of the charger, the ear unit has a red light that sometimes comes on when the charger is attached.  I have to wiggle it a bit and set it down just right to get the light to stay on.  I have never seen the light go green or blue when on the charger, so I never know if or when it is fully charged.  Also when new, the volume seemed much louder.  The volume control still works, but it just seems as though the loudest setting is not as loud as it used to be.  So I have trouble hearing conversations while driving, which is the only time I use it.  For that reason I have ordered the Voyager 510 model, in hopes it will be as comfortable and provide better sound.