Time to choose: This month, over 50,000 students (together with their parents) are selecting their Leaving Certificate subjects. Students should be very, very careful about their exam options. The following is a rough guide

How many subjects should a Leaving Certificate student take?

Most students should take seven subjects for the Leaving Certificate. The best six will be used to calculate the student's points.

If they are taking more than one ordinary-level paper (for example maths and Irish) and want the option of having six higher-level subjects for points purposes, it might be worth considering an extra subject. This advice comes with a health warning. There is no such thing as an "easy" higher-level subject and every subject requires a certain amount of study on a daily basis.

Taking eight Leaving Cert subjects is a major undertaking. If the eighth subject is being taken outside school, you have to take into consideration the time involved in travelling to and from a grind school. All this takes from the time available to work on the seven subjects studied at school.

Students taking certain combinations of Leaving Cert subjects can take a Leaving Cert Vocational subject, which is a mainly portfolio-based assessment. Students awarded a distinction can gain up to 70 points from this subject.

Should clever students take on extra subjects if the school timetable limits their choice?

If there are timetable problems, which make it impossible for a student to take a subject they particularly enjoy, they could consider taking it outside school - provided they are disciplined and highly motivated. Otherwise, forget it.

What happens if I don't take higher-level Irish?

Then you could have real problems. The main consequence is that you are precluded from studying to be a primary-school teacher in any of the Irish training colleges. You can also forget about degree programmes which have Irish as a core subject.

What happens if I don't take higher-level maths?

A similar story. There are several degree programmes from which you will be excluded if you do not take higher-level maths. These include many engineering courses, some computer courses and some others in science, information and computer technology. The list also includes most degrees that include maths as a core subject.

Students interested in careers which follow on from such courses, can always start with certificate programmes which may only require ordinary-level maths and progress through to diploma and then on to a degree programme. But that can be a long process.

What happens if I do not take a language other than Irish and English?

The colleges of the National University of Ireland demand a pass in a third language for entry into any of their colleges. These colleges are UCD, NUI Galway, NUI Maynooth, and NUI Cork.

What's the easiest subject in the Leaving Certificate and what's the hardest? Are there any easy higher-level subjects.

Here is the situation at a glance.

Irish: Those taking higher-level Irish tend to do well with almost 84 per cent achieving this level.

English: 76 per cent of higher-level candidates reach this standard.

Maths: 75 per cent of those taking maths at higher level succeed.

History and geography students do less well, having, on average, a 70 per success rate.

Foreign languages: German is "easier" than French. Some 80 per cent of German students get a honour, but only 68 per cent of French students do likewise.

Art: Art students have an almost 85 per cent success rate.

Science subjects: Far more students take biology than physics or chemistry, with chemistry students faring best - with a 77 per cent honours rate - and physics students performing worst with a 67 per cent success rate. Biology students fall in the middle with a 69 per cent success rate.

Technical subjects: The small number of students who take technical subjects at higher level do very well, achieving grades between 74 and 82 per cent.

Home economics - social and scientific: Be careful! This is regarded as an easy subject and attracts a large number of students at higher level. But the success rate at higher-level - at 66 per cent - is among the lowest of all the subjects. Some bright students spend little time studying the subject and assume they will pocket an honour. This is a dangerous game. Avoid it!

Music: In contrast, music students almost all (95 per cent) succeed in achieving a pass at higher-level.

Business subjects: Business is by far the most popular subject, over 16,000 students take it. Economics attracts less than 4,000. Both subjects have a 70 per cent success rate. Accounting has a somewhat higher success rate of 75 per cent.

What combinations of subjects should be avoided? And do I need certain skills to do certain subjects?

Students should be aware that some subjects have a large amount of reading associated with them e.g. history. Others require strong maths skills, for example physics and, to a certain extent, economics.

Other subjects, such as business, require students to be very aware of news and current affairs.

Those taking languages need to be aware of the growing importance of the aural and oral aspects to the examination.

Some subjects have a more practical hands-on application that is attractive to many students, for example the technical subjects, plus home economics - social and scientific.

One piece of advice: be honest with yourself about your particular strengths. If you have an aptitude for a particular subject you can opt for it. But if you don't, be careful.

How can I ensure that my subject choices will not stop me taking particular options at third-level?

The Irish Times published a full list of the minimum subject entry requirements for all degree, diploma and certificate courses in a January 7th supplement.

When you are deciding which subjects to take in the Leaving Certificate, remember that this decision will have long-term consequences and affect the range of careers that are open to you.

A decision not to take any science subject or not to take a foreign language will have major implications.

If a student is making their subject choices and has not, as yet, decided what career they wish to follow after leaving school, I would advise them to keep all their options open.

My advice? Ideally, take a science subject and a foreign language and cover your risk.

• Brian Mooney is president of the Institute of Guidance Counsellors. He works as a guidance counsellor at Oatlands College, Stillorgan, Dublin.