https://www.ngdc.noaa.gov/geomag/declination.shtml
Above is a link where you can figure out the declination based on your zip code. It changes over the years (as the article states) - so if you have thought your declination is zero for the last ten years, it probably has changed a little bit.
Maps will give the rate of change each year as well, so you don’t have to throw out that map from 1972. Of course the rate of change is just estimated. Hmm. I might have to do that - pull out an old map and see how accurate they were on their estimate!
Just checked. I am now 3 degrees West. Moving West each year.
but what does it mean?.....why should we care?