Can someone here tell me how long a Canadian can stay in the United States at a time? I drove here from Canada and return every 2-3 months. Is there a set limit and am I being recorded while I am here?

I sometimes leave my car at my girlfriends place in Florida and fly back to Canada so at times my vehicle is in the US for more than 6 months at a time. When I drive back to Canada will the Canadian border see that my vehicle was out of the country for such a long time and will this cause me any problems