There is probably no topic more discussed and debated among novice and seasoned cruisers alike than tipping: how to tip, when to tip, how much to tip, whom to tip -- and perhaps even why you need to tip at all. Yes, tipping etiquette and varying cruise line policies on the practice can be baffling indeed. Worse still, gratuities that you haven't anticipated can quickly eat into your cruise vacation budget. Here are our tips on tipping, so you won't be lost at sea when it comes time to show your appreciation for the cruise crew.

While, technically speaking, tipping isn't mandatory -- a tip, after all, is considered to be a voluntary expression of thanks -- you must consider that the gratuities distributed onboard the modern cruise ship are much more than mere bonuses.

There are exceptions, but most mainstream cruise lines pay the men and women who serve their passengers a low base wage (by Western standards). As such, on nearly all big-ship lines, crewmembers are dependent upon the generosity of travelers for a good portion of their income. The cruise lines' rationale for this compensation model, whether or not you agree with it, is that tips help incentivize higher service standards. And, of course, the cruise companies are all too happy to keep their cruises' advertised prices down by passing off some of the cost of employee compensation as added gratuity fees tacked on to your onboard bill.

On the other hand, many luxury and boutique cruise lines (like Azamara, Crystal, Seabourn and Silversea, among others) have no-tipping policies in place. In these cases, the staff service fees are built directly into the all-inclusive fares, and their crewmembers are paid accordingly.

Today, most mainstream cruise companies place automatic service charges on passengers' shipboard accounts, or offer the option for prepaid gratuities at booking, conveniently replacing the need for travelers to run around the ship handing out tip envelopes at the end of their cruise. The automation of the tipping process has been implemented for two main reasons.

The first is the rising number of international travelers on cruise ships, who do not always share the American mentality about tipping. With many passengers onboard from countries where tipping is not customary, automatic service charges help to guarantee crewmembers' compensation.

The second reason for the automatic charge is the proliferation of alternative dining venues. That a new ship will have multiple dining venues -- beyond the buffet and main dining room -- is now the norm rather than the exception. In the past, passengers dined at the same table each day for three meals and then tipped their assigned waiters and waitstaff. With flexible dining plans and numerous dining options now in vogue, passengers are no longer tied to just one team of waiters. Over the course of the week, they may encounter a number of servers, making tipping more problematic.

Automated tips are typically dispersed across the entire service staff (including cabin attendants and restaurant waitstaff), and admirably include those who previously went unrewarded, like the servers in the buffet restaurants, where most passengers eat their breakfast and lunch, and other behinds-the-scenes staff.

In short, gratuities should not be viewed as an optional "extra," but more as a required service fee, which ensures fare wages for the hardworking cruise crew. Accordingly, when planning your cruise vacation budget, be sure to factor in the estimated cost of gratuities for the duration of your sailing.

The traditional cash-in-envelopes method of cruise tipping is now almost entirely a thing of the past. Opt into the cruise line's automatic service charges, and you'll not only ensure fairness to all staff, but also save yourself the headache of having to crunch numbers and track down numerous crewmembers on the final evening of your cruise. The charges, applied per passenger, per sailing night, will be conveniently added to your shipboard, credit card-backed account, and in some cases, can be prepaid at the time of your cruise booking.

Special note: Children are not usually exempt from auto-tipping (with the exception of infants and toddlers, on some lines), which seems fair, given that they certainly contribute to in-cabin messes, and require as much attention -- if not more -- as any adult in the restaurants.

Because tips are technically voluntary, most cruise lines do allow passengers to opt out of the automatic service charge and to tip by themselves in cash. However, since it is practically impossible to individually tip all the people in front of and behind the scenes whose efforts enhance passengers' shipboard experience, we would discourage going this route.

Keep in mind that even if you've opted in for automatic gratuities, or are aboard one of the luxury cruises where tipping is included in the upfront rates, you should still bring along a cash stash for additional tips for exemplary or optional services (American dollars are gladly accepted worldwide, so come stocked with singles, fives and tens). These cash tips should generally be passed along hand to hand -- for formality's sake, you might consider sticking money in an envelope (envelopes are usually available from your cabin's stationary supply or at the ship's reception desk), though that extra step isn't necessary.

As mentioned above, we suggest sticking to automated tipping, which can sometimes be prepaid upfront before your sailing even begins, or applied to your shipboard account as a daily or cumulative fee. Personally, we like pre-paying the amount in full, when possible, so a hefty balance statement at the cruise's end doesn't interfere with our post-vacation glow. (The bar bill and spa charges can be a buzzkill all by their lonesome!)

If you feel that this automated service charge should be adjusted -- either increased or decreased -- you should make the request with guest services toward the end of the cruise, once the standard of service onboard has been properly assessed. Note that any desired adjustments must be made before disembarking.

For any additional tipping, to mark particularly outstanding service, the general rule of thumb is to hand out cash tips on the last day of the cruise. Don't wait till the morning of disembarkation, when everybody is in a frenzied transition mode and it might be difficult to locate the staffer you're after.

But there are exceptions to this rule, when pre-tipping can be quite strategic. One instance is your cabin steward, especially if you have special requests or require extra service (e.g., you want a bucket of ice delivered to the cabin nightly; plan to do a lot of entertaining in your cabin; or if there is an infant or someone who is ill in your party). A well-placed tip at the beginning of the cruise can do wonders to help ensure that he or she happily obliges.

Another instance might be a bartender at your preferred onboard bar -- a hand-passed gratuity on the first day of the sailing can go a long way in having him or her recognize your face in the crowd, and remember just how you like your drink. Or, perhaps, there's a window table for two that you have your heart set on in the main dining room -- a nice tip to the maitre d' on day one can help ensure that she or he never fails to have that table waiting.

Room service stewards should be tipped on the spot, as should non-cruise workers like in-port baggage handlers or tour operators on shore excursions     (Elissa Garay)