In some parts of the US, for example, a tip of 20% is the norm, while no tip at all is expected in Japan. We asked etiquette experts for their advice on tipping for all occasions.
Most people are happy to leave a tip in a restaurant if they feel the service has been good.
According to Debrett's, which describes itself as "the modern authority on all matters etiquette, taste and achievement", you should always "leave an appropriate tip, except when service has been exceptionally poor". The big question, though, is how much you should leave.
The accepted amount in the UK used to be 10% of the bill, but this issue has been confused by many restaurants adding a 12.5% service charge to the bill automatically.
Meanwhile, research from foreign exchange specialist ICE Direct indicates that while you should leave 15% in a restaurant in Toronto, 5% is acceptable in a posh Paris eatery.
Tom Johnson at ICE Direct said: "Tipping varies from country to country, so it's difficult to know how much is too much. In some parts of the USA and Canada tips can be in the region of 20% – and it's seen as the height of rudeness not to tip.
The good news if you are unhappy with the service provided is that you can ask for any automatic charge to be removed without resorting to vulgarity.
"Some establishments will add a discretionary percentage automatically," Debrett's said. "You are not obliged to pay this if service has been noticeably poor, and in some circumstances it is acceptable to ask for it to be removed."
However, if you are happy with your waiter/waitress, it is good manners to pay any service charge included and to add one if not.
Debrett's said: "Service not included means just that, and it is usual to offer at least 10%."
In smarter hotels, staff generally expect tips for the services they provide, such as carrying luggage to your room.
In this instance, Debrett's advises a "small gratuity of one or two pounds, dollars or euros, for example", per piece of luggage handled.
If you are happy with the way your room has been cleaned during your stay, it is also usual to leave a banknote in your room for the housekeeping staff.
Unlike in the US, valet parking remains a rarity in the UK. However, Debrett's has the following advice if you come across it.
"If you unexpectedly encounter complimentary valet parking, react with aplomb," it says. "Hand your keys to the attendant and walk away without a backward glance; never apologise about the state of your car, or plead with them to drive carefully.
"When they return the car, and if you are satisfied with the service, then offer them a tip of at least £1."
In the UK, many people do not tip taxi drivers at all unless they have been kept waiting, for example.
However, Debrett's advice when it comes to taxis is to tip around 10%, while the ICE Direct guide suggests simply rounding the price up to the nearest common denomination in Bangkok, Thailand, but adding up to 20% if you don't want your Miami taxi driver to think you are tight.
It is best to consult a travel guide before heading off on holiday as a result.
The practice of tipping a hairdresser or beautician has become less common in recent years.
However, if - as in a restaurant - you are happy with the hair cut, massage or facial you have had done, it is a nice gesture to leave a little extra for the individual concerned.
The best approach is probably to follow Debrett's advice: "In hair and beauty salons, use discretion but err on the side of generosity".