However, when I do the calculation for my own behavior, I never seem to get my money's worth from the unlimited. This is because the unlimited card price is always higher than the cost of buying a per ride card if you are only using the card to commute to work during the week. Even if you are using it for one round trip on the weekend, you would still pay less by buying a "pay-per-ride" card unless you buy a 30-day card.
The following table shows the cost of each unlimited ride card, followed by the amount of trips that could be purchased for that same amount. Because the MTA gives a 15% bonus for all "par per ride" purchases over $7, the nominal value in the table shows the value that will be shown on your metro card if you purchase a pay per ride card.
|Unlimited Days||Unlimited Cost||Nominal Value if purchased as a "pay per ride" card||Trips if purchased per trip||Trips used if going to and from work only, 5 days a week||Trips lost if buying unlimited only for work versus purchasing regular card||Also one weekend trip each week||Trips lost if buying unlimited versus purchasing regular card with 1 weekly fun trip|
The first line shows the one-day card, which can be purchased for $7.50. You can use that same $7.50 to purchase $8.63 in value instead, which will be good for 4 trips plus $0.63. Thus, you'd only want to get an unlimited one-day ride if you were making at least 2 round trips.
The 7 day unlimited costs $25. If you use that same $25 to instead purchase a pay-per-ride card, you get $28.75 of value, entitling you to 14 trips (plus $0.75 additional of stored value). If you go to work every weekday during the 7 day period, you'd use just 10 trips (5 round trips). If you also use the card for one round trip during the weekend, you are up to 12 trips, still 2.4 trips short of what you could have purchased with the $25 for a pay-per-ride.
As the table shows, you are always better off purchasing pay-per-ride cards instead of unlimited cards if you are just using your metro card for commuting. Even if you take one round trip in addition to work every week, only the 30-day unlimited would be worth it, and this only if you go to work every weekday during the period and use the card once each weekend. Many people work at home from time to time and there is typically a federal holiday each month, so the 30-day figures are optimistic.
The other issue with the unlimited is a psychological one: I get upset if I forget my unlimited card or end up not taking the subway a couple days when I could have used the card. With the pay-per-ride, you only pay for what you use. Perhaps more annoyingly, the pay-per-ride cards display the amount left each time you enter the subway, but the unlimited cards do not tell you the number of days left on your card when you enter the subway, and thus, if you don't keep track it yourself, you will be jammed in the legs with a locked turnstile at least once a month when you purchase an unlimited card.
I realize there are some who not only commute to work but also very frequently take subway trips to go out or run errands. For those, the unlimited cards may be worth it. For others, stick with the pay-per-ride.