It all depends on how old the chart is and how far you are going. No problem for a day sail across the Bay or Sound but you want current charts if there is any real distance involved, because a fraction of a degree can make you miss entire countries.And I'm curious about the rapid movement of magnetic north over the last few years. Has this affected your navigation a lot?
From the aviation side and with respect to how fast deviation is changing and making charts obsolete, I know that runways are marked to the nearest +/-5 degrees magnetic and the frequency to re-mark them has increased. It's really odd to come back to an airport you've known forever and have to call a familiar runway by a new number.