I check to see if I can put February 30th (less common of an error these days) on the oldest year they'll let me. 29th if 30th isn't an option and try to select a really old non leap year
On the one hand, I disapprove of unnecessary math, but on the other, I approve of the Hitchhikers Guide to the Galaxy reference.. That's too big a dilemma before my second cup of coffee!