Well, if you do, life will never be the same again. If you don't, you'll spend your life wishing you had.
Abroad, you may find a better climate, and a lifestyle that goes with it. Your accommodation may be provided (though not in Europe) and although it may be more basic than you are used to, you will probably be financially better off, especially if you have a home to let in Britain. You may be surprised at how little you miss things you always considered essential and, in a warm climate, you may reassess the essentials of civilised living.
Within five weeks you will get to know more people than you did in five years back home: expatriates tend to be gregarious and a new recruit will eagerly be sought out to swell the ranks. If you tell yourself that you didn't travel 3,000 miles from Britain to meet the British, you may well find the locals eager to befriend you. You may be exotic in their eyes, or provide an opportunity to practice their English, or find out about the West. You may even be thought of as a means of procuring a visa or passport to Britain, so beware of too much generosity. But this is all good for your self-esteem. Then you have a decision: to learn the local languages or stay locked in English.
As your school will possibly be international, and probably in a capital, it will also charge high fees and draw on embassies, international companies and the local rich for its clientele.
You may not have encountered such sophisticated and well-dressed students in Macclesfield; multilingual, travelled and poised, they will probably lack the laid-back cynicism of their British counterparts, and may surprise you with their willingness to learn, their competitiveness, and obsession with marks and tests. You may rediscover yourself, and your enjoyment of teaching. It can be invigorating.
Responsibilities may come your way more quickly than you could have hoped for back home, and you will discover a versatility you never thought you had. As a Briton, you may be looked up to (and able to charge higher fees for private lessons as a result) but your heart may ache to see teachers embrace enthusiastically such doctrines as mixed ability, which are being re-assessed in Britain.
You may question the wisdom of experts: what seemed a splendid idea to an educationist at their word processor in Birmingham just doesn't seem to work in Brunei. Is what works in Britain valid for Japan or Jakarta? Is learning by heart totally bad? And so you may discover that neither Britain nor you have all the answers, and that both may have a lot to learn from what others do, as well as teaching them our way. Education is, after all, a two-way process.
You will discover the difference between being a traveller and being a tourist; and sorting out how to pay (and read) your first lot of electricity and phone bills will make you realise that you're not on holiday.
You will develop a keener awareness of what Britain really is when you view it from afar. Generalisations about Arabs, Africans and the Third World may take on new dimension.
You may be surprised to discover that the Third World can in many ways be more modern than Britain (because its infrastructure is newer) and that many people will feel rather sorry that we live and work in such old buildings, when most of theirs are new.
It can be a surprise to find that a phone line is easier and quicker to obtain in Amman than Aldershot. You will discover that many Arabs are fair-haired and Christian; and that Taiwanese are probably more up-to-date with American pop culture than you are. You will be surprised; and whatever your age, you will mature.
But are there no drawbacks? At first, you may enthuse about your new domicile and reject all that is British - the consequence of "going native" too enthusiastically - and thus bore and irritate friends and family at home. Or you may criticise everything in your new country, and blame it for not being Britain; then wonder why you fail to make friends. You may be irritated when you return to Britain on holiday to find how little interest your friends have in all that you want to tell them. They can't relate to it. Your lives have begun to diverge.
Currencies can fluctuate, and it is best to be paid in Sterling or US dollars. You probably won't be, and you may find that your salary can drop alarmingly in Sterling terms and that you are less well off than you thought. You may even find that exchange regulations change and that restrictions are placed on remittances, so that your bank manager at home gets restive.
Also, the high salaries once earned, especially in the Middle East, are less common now. In Europe you're unlikely to be paid a high salary, and you'll have to rent your accommodation. It's assumed that private lessons will bridge the financial gap.
Take advice about pensions. Don't let a current scheme lapse and keep up National Insurance payments. A thirteenth-month salary is commonly paid, and is intended for this, rather than to spend on travel and treats. What medical care is there? Don't accept vague promises of "generous cover": make sure it's enough and get it written into your contract. Take out a private international scheme to be on the safe side.
Other countries have national curriculums too, and they can also be unbearable. You may also have to adhere to complex systems of recording marks.
Job security may be a thing of the past, if you move abroad. Your contract will probably be for two years and will not automatically be renewed, so what do you do then? You will find it harder to return to Britain than it was to leave, and you will find "re-entry" baffling and infuriating. Your experience seems to count for nothing; though you probably work harder than ever before, it dawns on you that people think that you have been on an extended holiday.
It will be depressing to find how many potential employers assume that things beyond Europe are primitive, and you wonder whether to tell them that the computer room you've just left in Singapore was three times the size of the one the head has just proudly shown you, and the theatre of your school in El Salvador made this one look like the multi-purpose gym that it is. There seems resentment that you have left "the system" at all. You detect a whiff of envy among the ignorance. The insularity will astound you. Do you want to come back, after all?
Be aware of the "came for one year and stayed for 10" syndrome. You may hate the first year, filled as it is with the stress of settling in, finding plugs that fit, not finding someone to mend the washing machine, and that you keep comparing it with home: it was all much better in Britain. You can hardly believe the irony. Then in your second year, second time round, when you are advising the newcomers about how to get their washing machine repaired, it all seems much easier and the ordeals of the first year become a sort of cement which attaches you to your new home. Britain is going to the dogs. And so the years roll by.
So, should you go abroad? Shouldn't you? The choice is yours. I don't think I have ever met anyone who regretted working abroad, and no one is ever unchanged by it. Life will get more complicated if you go, and probably more rewarding. But don't be naive: be aware of the pitfalls, and seize the opportunities. And ask yourself: how would life have been better if you had stayed at home?
David Thompson's advice is based on 15 years' experience of teaching abroad.