Cruise rates can be pretty darn appealing these days, especially if you're cruising during slow periods -- like right now, during the fall. But before you get too excited by $100 per diems, keep in mind there are extra costs that will take some of the joy out of the bargain.

Aside from expenses like airfare to the ship, drinks and shore excursions that all but the handful of ultra-lux lines charge extra for, you also need to factor in tips for the crew. They can really add up if you're traveling as a family or are doing a long itinerary -- you'll be expected to tip on a per day basis.

Although technically you can choose how much you want to tip the crew (unless you sail with one of those few "no tipping" lines, including Silversea, Seaborn, Radisson and SeaDream Yacht Club), the cruise lines aren't shy about offering guidelines. In fact, I've talked to passengers that feel the tip reminders throughout the cruise are down right oppressive.

Some of the tipping frenzy is mitigated when the cruise lines add gratuities right on to your onboard charge account. (Passengers get a bill the last night of the cruise listing all of their charges for the week, you can settle up by credit card or cash.) Though you'll still be out about $70 per week (or $10 per day) per person (some lines suggest half for kids) to cover tips for your waiter, bus person, and room steward, you won't have to deal with the notes and reminders employed by ships that still work on a cash tip system. Some lines allow you to pre-pay your tips when you book your cruise, though if you choose this option, then you won't be able to adjust them up or down according to the service you receive once on board.

The cashless tipping option is especially convenient since most ships have multiple restaurants and you might not ever have the same waiter twice and would have trouble knowing whom exactly to tip. That said, some cruisers miss what they feel is the more personal expression of gratitude for good service -- a handshake, a slap on the back and a wad of greenbacks.

No matter your personal feelings, here are the latest tipping policies and "suggestions" of the major cruise lines. In all cases, you can always tip less, more, or not at all, if you're not satisfied with the service. If you're on a ship where tips are automatically added to your tab, to get the amount changed or removed, you'll have to pay a visit to the reception desk to make changes. If you have been satisfied with the service your waiters and cabin stewards have provided, tipping is essential since these crew members rely on tips for the vast majority of their earnings -- whether that seems fair or not, that's how the American cruise industry operates.

Carnival Cruise Line (tel. 800/327-9501; automatically adds $10 per person per day to your onboard account. Parents are not expected to tip for children under age two.

Disney Cruise Line (tel. 800/511-1333; gives passengers the option of tipping in cash or automatically, if you pay a quick visit to the reception to get them put onto your bill. Here's what Disney suggests per person (kids and adults alike) per cruise. 3-night cruise: waiter $11; assistant waiter $8; headwaiter $2.75; cabin attendant $10.75 (for a total of $32.50). 4-night cruise: waiter $14.75; assistant waiter $10.75; headwaiter $3.75; cabin attendant $14.50 (for a total of $43.75). 7-night cruise: waiter $25.75; assistant waiter $18.75; headwaiter $6.50; cabin attendant $25.25 (for a total of $76.25).

Holland America Line (tel. 800/426-0327; automatically adds $10 per person per day for all passengers.

Norwegian Cruise Line (tel. 800/327-7030; automatically adds $10 per person per day for adults and $5 per person per day for children under age 13.

Princess Cruises (tel. 800/774-6237; automatically adds $10 per person per day, regardless of age, to your onboard tab. If you have young children, you are invited to adjust the amount based on the amount of service your child has received.

Royal Caribbean (tel. 800/327-6700; and Celebrity Cruises (tel. 800/437-3111; give passengers the option of adding tips to their onboard charge accounts. If you don't choose this, the default method is cash. The lines recommend a total of $10.50 per person per day, broken down accordingly: waiter, $3.50; assistant waiter, $2; assistant maitre'd, $0.75; cabin attendant, $3.50; assistant chief housekeeper, $0.75. For children, under 12, the two lines recommend you tip half of the adult amounts.

When it comes to tipping your favorite bartender, on most ships your bar tab includes a 15 percent gratuity. If he really poured a good gin and tonic, no one's going to mind your slipping him some extra cash. For spa treatments, a 10 to 15 percent tip is typically charged directly on to your bill; if it's not, don't worry, you'll be reminded that tipping isn't included. In this case, you can write a tip in (or take one off if your Shiatsu wasn't up to par) and it'll be charged to your shipboard account. Most ships also have "alternative" restaurants come with an extra fee that's called a cover charge or tip that will run you between about $10 and $30 per person. For room service, tip as you would in a hotel; I usually give $1 or $2 each time. In the "them too?" department, some passengers tip the youth counselors at the end of the cruise if their kids spent a lot of time in the programming and/or group babysitting service, giving cash directly to the counselors or into a box or bowl that is sometimes set up in the playroom.

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