The deepest roots of the custom of tipping are elusive. The evidence points to tipping going back to the age of the Romans, or at least the invention of money.

There's a broad range of etymologies for the term "tipping". The most basic point of origin is the Latin word 'stips', which simply means a gift. The Middle English scholars lay claim to Geoffrey Chaucer, who used the term "to tip" to mean simply "to give", as in "tip us a kiss!" or "tip me five pounds until pay day." The actual phrase also appears as "tip me that cheate" (give me that thing), in the "Beadle of Bridewell" by Samuel Rowlands in 1610.

The charming story we all have probably heard is that "TIP" was an acronym for "To Insure Promptness". Back to the 18th century, the story goes that patrons would drop a few (audible) pence into a box bearing the label "to ensure promptness" as a measure to encourage a greater display of vigor on the part of the generally listless attendants. But it is more likely that this story is another urban legend, or what we call a "backronym", an amusing acronym story made up to explain a word which wasn't originally an acronym at all.

Tipping spread from England to colonial America, but after the American revolution it was temporarily frowned upon as a left-over custom from the British class system. After all, if one only tips one's inferiors, well, - ahem! - there are no 'inferiors' in the Brave New World we created, right? The culture shrugged this off after a few years and the custom of tipping resumed to what it is today. When it comes to mixing politics with day-to-day commerce, even the Communist countries have not entirely succeeded in eliminating the practice of tipping.

Another apocryphal story has it that a California restaurant had a sign on the door "Please do not insult our staff by tipping!" but inside, there on the counter was a jar by the cash register clearly labeled "Insults".

These days, of course, everybody from taxi drivers to somaliers depends on tips for a substantial part of their income. If customers didn't tip, presumably the staff would expect to be paid more, and restaurant bills and taxi fares would consequently be higher. The fifteen percent standard is mostly a question of what the market will bear. In New York, the figure these days is twenty percent, and if you have lived in New York, you know why. And European restaurants generally add a ten percent gratuity to the bill.

If your restaurant has a policy of adding a percentage to the bill as a gratuity, it is expected that you have a sign somewhere in the general vicinity of the cash box stating this fact. Also, many restaurants have a policy of the waitstaff pooling their tips on a pot, which gets divided evenly amongst them at the end of each shift. Still other restaurants ask that non-tipped employees such as cooks and janitors receive a percentage of tips as well. In Brazil, a simple service charge is added to the bill and split among the staff, and that's that. Whatever your custom, try to feel out the staff to see what they prefer, and then get the policy in writing and include it with new employee orientation.

Positions outside the restaurant trade have more recently picked up the tipping custom. Bellhops, taxi drivers, and even barbers variously accept tips. But in some countries, the police expect a small gratuity! This is not the same thing as corruption - well, not quite. Police officers and other civil servants in third-world economies openly solicit tips, gifts and dubious fees using any of a set of local euphemisms. For example, a traffic policeman in Mexico might ask a commuter to buy him a "refresco", which is a soft drink, while a Nigerian officer might expect "a little something for the weekend.". This is less about graft and corruption and more about the shockingly low wages these professions receive in these countries. A visitor from elsewhere will usually not be "hit up" for a gratuity, but you never know.

Tipping is more widely supported amongst the civil servants in third world countries. For instance, a dog license application might be accompanied by a minor tip "for their trouble".

Back in the US, the state regulations on declaring taxes on tips varies by the state. But an interesting fact worth noting is that most state jurisdictions make a distinction between "voluntary tipping" and "expected tipping". For example, a tip at a restaurant, while not required, is for the most part expected. Giving a dollar to a barista for making a latte is not expected, and is therefore a "voluntary tip" that in most jurisdictions does not need to be claimed to the IRS.