If you're too immersed in the modern age to work with paper maps and human interaction, try www.tripplanner.mta.info or www.hopstop.com for MapQuest-like help. Both are surprisingly functional on BlackBerrys and Treos, though Trip Planner is New York-only and requires fewer clicks. Check for notices about service changes and get a second (human) opinion.

MetroCard math Here's the basic rundown: Official price is $2 a trip, but if you buy five, the sixth is free, effectively cutting the price to $1.67 a trip. (Multiple riders can swipe the same card.) Compare that with the individual unlimited passes — the one-day for $7, worth it if you're going to take at least five trips before 3 a.m. the next morning, and the $24 seven-day pass, if you're sure you're taking at least 15 trips.

Dirt and noise The subway has been around since 1904, so expecting it to be as clean and quiet as Washington's or even Mexico City's is unreasonable. (Mr. Guerrero, are you listening?) That's not grime you're seeing, it's historical charm. And those creatures scurrying down the tracks are, um, underground squirrels. As for the screeching cars, how else can you tell the train is coming? A computerized announcement? Flashing lights? So unromantic.

Safety No one will fault you if you want to take a cab back to the hotel at 3 a.m. But you don't have to. Around 3 a.m., the Manhattan trains can be so jammed with late-night revelers (and a few jealous bakery workers) that you'll feel silly for even having worried about your safety. Two incentives to take a cab late at night: trains are less frequent, and should you fall asleep on the way, the cabby will wake you up at your destination; subway cleaners will wake you up at 4:30 a.m. — in the Far Rockaway section of Queens.

The heat In summer, stations can be a tad stuffy. Some prefer the terms “stifling,” or “living inferno.” One possible solution: come back in the winter. Another: buy cold water from the underground newspaper vendors (it looks as if they wouldn't have a refrigerator back there, but nearly all do). Once you realize those people are stuck there all day, it's harder to feel sorry for yourself.

The wait Sure, but a taxi doesn't provide entertainment. Check out the crazy fingernails on that woman. Is that guy really playing the theme from “Happy Days” on his sitar? Who'd have thought there'd be so much legit artwork? And a special for science lovers: understand how anthill traffic works by observing the teeming underground corridors of the Times Square stop, where miraculously people never bump into one another.

Bearing the noise There are five kinds: a) The rumbling that says the train is coming; b) the honking that indicates a train is bypassing the station; c) the cursing that follows; d) the unimportant, clearly enunciated announcements (“thank you for riding New York City transit”); and e) the vitally important incomprehensible announcements (blah-blah-will-be-skipping-blah-blah-now-running-express-blah-blah-shuttle-bus). Solutions: bring earplugs, and ask for help.

Finding a restroom Good luck.