I have a name brand adapter that has two USB ports on it that plugs into the cigarette lighter. Is it safe to leave it plugged in all the time or should I remove it when it's not in use?

 

I remove mine when not in use. No reason I just do. Probably to avoid prying eyes, seeing what goodies are in my HHR and are they worth stealing.

 

I unplug mine hen it is not in use though I do keep a small rechargeable flashlight that is LED and shines in blue when it is plugged in. That way I always have a light handy if I need one. I found it at Home Depot a few years ago. There is also one in my wife's car.

 

I put one in my Ranger about a year ago. I never remove it and hasn't caused any problems.