There's no such thing as "should happen." Every company underwrites differently, uses different criteria to set rates, weighs different factors differently. If you have an agent, call them once you retire and tell them you are no longer commuting because you retired, and that your miles driven per year are going to drop from X to Y. If you don't have an agent, call your insurer directly and do the same. That's really the only direct impact the act of retiring, by itself, would likely have on your rates. Other factors might also be at play (age, etc.), but as I said, every company underwrites differently.