I am soon to renew my Retirement Visa.  It is my understanding that I can renew as early as 30 days before my expiry date, and that I will not be penalized (i.e. lose any of my current 1 yr. visa) if I do so.  If it matters, I will be applying in the Amnat Charoen Immigration District.

You understand correctly - if that is what you want to know.

Yes that is correct. In fact, at some offices 45 days early is accepted without any excuse. The new annual extension always begins after the old one expires regardless of how early the application is made. (So no penalty.)