In my last two columns, I have discussed the first two elements of a legally enforceable contract.

First, the acceptance of a contract must exactly fit what was offered for there to be a deal.

Next, something must be exchanged between the parties at the time of the making of the deal. This is consideration.

Today, I will examine who has capacity to enter into a contract.

Generally speaking, the law presumes that everyone has what is termed "capacity" to enter into a contract.

However, there are a few groups that are said to be under an "incapacity".

Today, I will discuss minors and people under mental incapacity.

The presumption that all parties are of proper capacity to enter into a contract is not the case when dealing with minors, defined by the law as those under the age of 18.

This does not mean that all contracts entered into by a minor are void.

Contracts for necessaries, or employment, are examples of contracts that will be considered valid.

Necessaries are goods or services that are said to be necessary to the minor.

For example, if a shop owner sells a minor a regular jacket on the promise that the minor will pay for this jacket, the contract is enforceable even though the minor is not of age.

This is because the contract is for a necessary article - a regular jacket.

Necessaries cannot be extravagant, merely ornamental or for uses of comfort or convenience only.

Other examples of necessaries are food, drink, lodging and medicine.

Any contract entered into by a minor for these things will be valid.

Necessaries is a relative term which is to be construed with a reference to the minor's age and situation in life.

Services could also be necessaries. For example, a contract entered into for medical treatment by a minor is enforceable.

The most important points to remember about contracts for necessaries are that they must be beneficial to the minor and they will not be binding on the minor if they contain harsh and oppressive terms.

A contract of employment will also be valid, provided it is for the benefit of the minor.

But what happens if a minor misrepresents their age?

If a minor agrees to buy a bicycle, does their status as a minor prevent the person who sold the bicycle to them from any recourse when the minor fails to pay for the bicycle?

In this case, the law protects those who are under age so the contract is unenforceable. However, the minor would not be allowed to keep the bicycle.

Probably the most pressing question on every parent's mind is what if little Johnny goes out and signs a contract for that new scooter?

Are you as the parent responsible for contracts entered into by your minor children? The short answer is, thankfully, no.

Generally, apart from situations where the parent is involved in the deal, parents are not liable for debts contracted by their children.

In the case of mentally disordered persons, the general rule is that they are bound to the contract unless they can show that they did not understand what they were doing owing to this disorder, and that the other parties to the contract also knew - or ought to have known - that they were mentally disabled.

As above, the exception would seem to be when the contract is for necessaries.

There is no clear definition or measure of mental incapacity as the understanding and competence required will be measured against the particular transaction involved. The facts of each particular case will also have to be taken into consideration.

For example, if a party is of sound mind at the time the contract was made and subsequently becomes mentally incapacitated, this subsequent incapacitation does not affect the fact that the contract was made and understood.

Hopefully in the past four articles your understanding of a contract has been greatly increased. Instead of repeating the elements that have been examined over the last four weeks, the most important thing to remember about contracts will be repeated.

Put them in writing.