Equitable maxims guide judges in the exercise of discretionary powers and the development of the law of equity. None of them are applied absolutely.
Equity provides a remedy against ‘unconscionable’ reliance on the common law.
Equity supplements the common law, it does not supplant it. It will generally only go somewhat further than what the common law allows.
Equity will not permit a person to rely on the form of the law where this would be unconscionable.
Equity will not permit statutory requirements to be used unconscionably, unless this would undermine its central policy: Shah v Shah  3 WLR 31.
When seeking discretionary relief, the claimant must not have acted unconscionably: Lee v Haley (1869) LR 5 Ch App 155.
If given discretionary relief, the claimant must then do what is fair. For example, if a contract is rescinded, they must allow the seller to retrieve the goods.
If a person has a specifically enforceable common law obligation, it will be treated as done in equity. For example, if A is obliged to grant B a legal lease, B will be treated as already having an equitable lease.
If a person takes an action which might be seen as either fulfilling or breaching an obligation, equity will interpret it as fulfilling that obligation. For example, a trustee who mixes trust money with his own money is assumed not to have spent the trust money if he makes a payment from that account.
An equitable owner takes their rights subject to all rights that came before it, whether they know of that right or not. However, it was suggested in Taylor v Russel (1890) 1 Ch 8 that ‘gross’ negligence by the earlier rights-holder allows the court to grant priority to the later right by making the rights ‘unequal’.
Equity will not normally assist a person who has not provided consideration. A sub-maxim of this is that ‘equity will not perfect an imperfect gift’.
Where there are multiple equitable shares in a property, equity will presume the shares are equal unless there is evidence to the contrary.
Equity will not generally grant relief if the hardship is the claimant’s own fault – particularly if it is the result of unreasonable delay.