We have spent winters south since 2004. On average we spend 165 to 175 days in the US. After our 3rd year we have filed the 8840 form every year. Have never heard boo from the IRS as to even if they received it. You also have to include every day even if you drive over to pick up a package and spend 20 mins.
Starting in July Canada/US will share info on your movements. The US will know exactly when you crossed back into Canada. Be a real bummer to be going to Fla for the winter and they decide you can't come in this year.
In all the years I have been asked once if I knew about the 8840 tax form and I said I have my most recent copy.
All the form does is tell the IRS you have a closer connection to Canada ie banks,licenses, voting etc.
It remains to be seen if the IRS will also allow an extension if the bill passes. If not your still under 181 days
