Each year I go out to NYC to visit friends and I always seem to miscalculate how much to put on my metro card to get me around NYC and always come home with monies on the card. Now it's not alot, maybe a $1+ or so, but is there a good math formula to use to best maximize my card? My friend I go in with lives in central Jersey and doens't go into the city very often so leaving him the card doesn't really mean much. On this coming trip, my plan is to ride the subway a few times, and take the Roosevelt Tram. I am looking at maybe getting on the subway maybe 5-6 times on my day visit.