What is more risky than being a pedestrian in Paris, more likely to get you a rude reaction than if you gate-crashed a royal garden-party, harder to calculate than the interest in the gross national debt of a developing country, and likelier to leave you feeling suddenly like a fifteen-year old again?

The topic, in case you haven't realised it, is tipping. In travel, there is hardly any aspect that varies more, causes travellers greater tension and confusion, or gets them closer to the point of exasperation more rapidly than this.

If you are amongst the great band of travellers who can trek the Himalayas with impunity, raft down the Amazon with nary a fear, weather sandflies, heat-rash, sunburn and frostbite without a whimper, yet find yourself developing a nervous tic when faced with the dilemma of whether or not to tip, or how much – then this is for you.

Rather than tipping the porter, here at last are some tips for you, to help you know when, or better yet, when not to tip.

Tip #1: If the hotel porter lingers aimlessly after bringing up your bags, don't put it down to your new perfume, exotic accent or the possibility he has nothing better to do. Pay him and watch him disappear – just like his smile will, if you don't pay enough.

Tip #2: Teach your bored and inquisitive small children that the money under plates and on saucers on neighbouring tables at the restaurant is not a sign that this is their lucky day.

Tip #3: If the taxi driver takes a well-aimed lob at the footpath with your best leather suitcase, it means he feels cheated. You can choose to pay up fast to preserve your remaining five pieces of luggage, or put the money into a fund for replacing them.

Tip #4: Some countries add the tip into the bill. They call it a service charge. Unfortunately there is usually not a corresponding disservice fine, for those with a poor attitude. A quick way to check what the local system is – if the waiters all look as if they holiday in Hawaii, chances are the tip is included. Even if it's not, they're obviously making enough without your contribution.

Tip #5: You do not ever need to tip:

Telephone operators

The person who pushes the newspaper under your hotel room door.

The hotel manager.

In America, you probably should tip everyone else, including (in New York) anyone who has a kind word for you.

Tip #6: The word 'tip' is said to have derived from the acronym of To Insure Promptness. Technically then, you do not need to tip a taxi driver who, unasked, delivers you to the airport via the scenic route, the bellboy when he takes thirty minutes to bring your things up three floors, or the restaurant staff if you could have had your dinner airfreighted quicker from home.

Tip #7: The reason, they tell us, that you are required to tip in some countries, is that the local wages are so low. Tipping augments a lowly wage to the point where it is livable. It also diminishes your cash-flow to the point that you might have to consider hitch-hiking home.

Tip #8: Some nationalities tip better than others. Try not to look like someone from one of these countries. The I'm-poorer-than-you look works sometimes, as does a wallet or pocket empty of local small change. Note: this does not work if paying by credit card.

Tip #9: Do a crash course in the local currency. You will earn instant respect if you inadvertently tip someone ten times their month's salary, but you may need to run for cover too as the local low-life will have you pegged as a Very Big Target for some further help in separating you from the rest of your earnings.

Tip #10. If all else fails, grin and pay up. After all you're on holidays. The service may be slow and the food only marginally better than your own efforts, but you don't have to wash up.