Fundamentals

Lease Agreement: What It Is and What to Review

By Daniel Sardá · Published on September 24, 2026

6 min read1,180 words

A lease agreement permits the temporary use of property in exchange for rent. Understanding its elements, obligations, and limits can help prevent disputes.

Renting a home, commercial space, or even equipment raises the same basic question: how can one person use another person's property temporarily without buying it? A lease agreement organizes that exchange. One party grants the temporary use or enjoyment of an asset, while the other pays a price or rent.

The agreement is not a sale. Its purpose is to allow use for a defined period and to allocate responsibilities: who delivers the property, what it may be used for, who bears particular expenses, and under what conditions it must be returned. Those rules make the arrangement more predictable for both the landlord and the tenant.

The general idea appears in many legal systems, but details differ by country and by whether the subject is a home, commercial premises, or movable property. This article therefore explains the arrangement in general terms and is not a substitute for reviewing the applicable law.

Key idea: A lease grants temporary use in exchange for payment; it does not by itself transfer ownership of the property.

What is a lease agreement?

In a lease of property, one person—the landlord or lessor—undertakes to let another—the tenant or lessee—use or enjoy an asset temporarily in exchange for rent. It is an agreement of reciprocal obligations: each party makes commitments that correspond to those of the other.

This formulation appears, with differences in language and scope, in sources such as Spain's Civil Code and Argentina's Civil and Commercial Code. It is not, however, a universal definition that applies in exactly the same way in every country.

In ordinary speech, terms such as “lease” and “rental agreement” are often used interchangeably. Legal terminology may vary. It is also important not to confine the concept to housing: it may cover commercial real estate and, depending on the relevant law, vehicles, machinery, or other assets.

The elements that shape the agreement

Although legal requirements are not identical everywhere, a clear lease should identify at least four features:

• The parties: who grants use and who receives it. It is worth confirming their identity and their authority or capacity to enter into the agreement.
• The subject matter: what property is leased and the condition in which it is delivered. A precise description reduces later disagreements.
• The rent: how much is due, when and how it must be paid, together with any agreed mechanism for changing it that is legally valid.
• The time period: the term, relevant dates, or a criterion for determining how long the relationship lasts.

These elements describe the core exchange, but they rarely exhaust the agreement. A home may include furnishings; commercial space may permit some uses and exclude others; a machine may require specialized maintenance. The document should reflect the actual characteristics of the property and the purpose of the arrangement.

Reciprocal obligations, not isolated promises

In general terms, the landlord must deliver the property and allow its use as agreed. The landlord will also commonly have duties related to its upkeep and the tenant's peaceful enjoyment, though the precise scope depends on the law and the agreement.

For their part, the tenant must pay rent, use the property for the agreed purpose, take reasonable care of it, and return it when the relationship ends. Here too, a general category should not be turned into an absolute rule: the allocation of repairs, expenses, damage, and liability may be governed by mandatory rules.

This reciprocity helps explain why a clear agreement protects both parties. It does not merely impose duties on the person using the property; it also specifies what that person is entitled to receive in exchange for payment. In that sense, a lease is a concrete application of voluntary contracts: it coordinates different interests through consent and enforceable commitments, within the limits of the law.

Key idea: Freedom of contract matters, but it does not make every clause valid. Capacity, good faith, and mandatory rules also set boundaries for the agreement.

What to review before signing

A useful checklist should not be mistaken for a universal list of legal requirements. Even so, clarifying certain points can help prevent the parties' expectations from diverging:

• the identification and condition of the property;
• permitted use and possible restrictions;
• rent, payment dates, and additional expenses;
• duration, renewal, and how to give notice that the arrangement will not continue;
• responsibility for maintenance and repairs;
• security or other guarantees, and the conditions for their return or enforcement;
• whether assignment or subletting is allowed or prohibited;
• the grounds and consequences of early termination; and
• the procedure for notices and resolving disagreements.

For example, when a person rents equipment for a business activity, it is not enough to write “equipment in good condition.” Identifying its components, documenting its condition when delivered, and specifying who performs routine maintenance make it easier to compare what was agreed with what occurred later.

Clarity is especially valuable where there is an imbalance of information or bargaining power. Reading before signing, asking for explanations of ambiguous terms, and keeping a copy of the agreement are simple precautions. A generic template may help organize information, but it does not ensure that the agreement complies with local rules or addresses the particulars of the case.

Lease, loan for use, and sale

Three arrangements may involve delivering property, yet they serve different purposes:

• In a lease, one party pays to use property temporarily and must return it.
• In a loan for use (often called commodatum), one party receives property to use and return, but the loan is essentially gratuitous in legal systems such as Spain's.
• In a sale, the agreement has an acquisitive purpose: property is delivered in exchange for a price. The method and time at which ownership transfers depend on the applicable legal system.

The decisive difference is not the document's label but the transaction's actual content. Calling an arrangement a “loan for use” when payment is required does not remove that consideration; calling a financed sale a “rental” does not change its purpose either.

Key idea: Look at what each party receives, what each gives in return, and whether the property must be returned—not only at the title on the first page.

The agreement and the applicable law

Contractual autonomy allows people to arrange the use of property without transferring ownership. That freedom works better where rights are defined and general laws are predictable rather than arbitrary. It also has limits: some rules protect interests that the parties cannot exclude through a contractual clause.

There is no single international answer on written form, deposits, rent increases, renewals, repairs, registration, termination, or eviction. Rules can vary by country, territory, type of property, and intended use. Residential leases in particular are often governed by special legislation.

Before signing, the most useful step is twofold: make sure the text describes the agreed exchange precisely, and confirm what the law of the relevant jurisdiction requires. A good agreement cannot eliminate every possible dispute, but it makes obligations visible, reduces ambiguity, and lets each party decide more knowledgeably what commitment it is making.