Frequency adverbs indicate how regularly an action occurs, from constant repetition to total absence. They respond to ideas such as always, often, sometimes, or never and help place the habit, the custom, or the likelihood of a fact. Their meaning is closely related to Adverbs of Time and to other adverbs that order temporal information in the sentence.

The most frequent adverbs in Spanish express continuity, repetition, occasionality, or rarity. In this group are siempre, a menudo, muchas veces, a veces, de vez en cuando, nunca, rara vez y casi nunca. These words are used to specify routine and the degree of frequency with much more precision than a simple temporal complement.

IdeaIdea	EjemploExample
Siempre expresa repetición total.Always expresses total repetition.	Siempre estudio por la mañana.I always study in the morning.
A menudo expresa alta frecuencia.Often expresses high frequency.	Voy al cine a menudo.I go to the cinema often.
A veces expresa frecuencia intermedia.Sometimes expresses intermediate frequency.	A veces salgo tarde.Sometimes I leave late.
Nunca expresa ausencia total.Never expresses total absence.	Nunca como dulces.I never eat sweets.
Rara vez expresa baja frecuencia.Rarely expresses low frequency.	Rara vez leo novelas.I rarely read novels.
Casi nunca expresa frecuencia muy baja.Almost never expresses very low frequency.	Casi nunca llego tarde.I almost never arrive late.

Some frequency adverbs are formed with suffixes and tend to appear in more formal or precise registers. Daily and weekly are common forms to express repetition every day or every week, and they relate to the processes of Formation of adverbs. In everyday speech, every day or every week may be more natural depending on context and register.

IdeaIdea	EjemploExample
Diariamente expresa repetición de cada día.Daily expresses repetition of each day.	Trabajo diariamente.I work daily.
Semanalmente expresa repetición de cada semana.Weekly expresses repetition of each week.	Reviso el informe semanalmente.I review the weekly report.
Cada día puede preferirse en estilo más natural o cotidiano.Every day may be preferred in a more natural or everyday style.	Camino cada día.I walk every day.

The typical position of these adverbs is before the conjugated verb, and that is why siempre estudio or a menudo salimos sound natural and clear. When the sentence has a compound verb, the adverb usually goes before the auxiliary, as in 'I have eaten' -> 'Siempre he comido'. These guidelines are explained along with the Placement of Adverbs, where it is also observed that in some speakers the adverb may go after the verb due to dialectal variation.

IdeaIdea	EjemploExample
El adverbio suele ir antes del verbo conjugado.The adverb usually goes before the conjugated verb.	Siempre estudio.I always study.
En un verbo compuesto, suele ir antes del auxiliar.In a compound verb, it usually goes before the auxiliary.	Siempre he comido.I have always eaten.
Algunos hablantes pueden colocarlo después del verbo.Some speakers may place it after the verb.	Estudio siempre.I study always.

With an infinitive or gerund, the adverb can be placed before or after the non-conjugated verb without changing form. Both positions are common, and the choice depends on rhythm, emphasis, and sentence style. This flexibility is useful to connect with the Adverbs of Manner and with other structures where position adds nuance.

IdeaIdea	EjemploExample
Con infinitivo, el adverbio puede ir antes o después.With an infinitive, the adverb can go before or after.	Siempre estudiar ayuda.Always studying helps.
Con gerundio, el adverbio puede ir antes o después.With a gerund, the adverb can go before or after.	Estoy siempre corriendo.I am always running.
La elección de posición puede cambiar el énfasis.The choice of position can change the emphasis.	Siempre cantando avanzo.I always advance while singing.

Nunca is a negative adverb by itself and does not need another negative word to form the basic negation. In many varieties of Spanish, the sequence 'no nunca' appears to reinforce negation and is common for regional or stylistic emphasis. This behavior relates to the Indefinite Adverbs, where negation and indefinition often interact.

IdeaIdea	EjemploExample
Nunca ya contiene negación.Never already contains negation.	Nunca fumo.I never smoke.
No nunca puede reforzar la negación.No 'nunca' can reinforce negation.	No nunca llego tarde.I never arrive late.
La doble negación puede ser frecuente por énfasis regional.Double negation can be frequent due to regional emphasis.	No nunca voy solo.I never go alone.

Frequency adverbs are invariable, so they do not change in gender or number. The form remains the same even if the sentence is singular or plural, or even if the subject is masculine or feminine. This stability sets them apart from other word classes that do change and brings them closer to the general behavior of [Adverbs of Place] and [Adverbs of Manner].

IdeaIdea	EjemploExample
El adverbio no cambia por género.The adverb does not change for gender.	Siempre trabajo contenta.I always work happily.
El adverbio no cambia por número.The adverb does not change for number.	Siempre estudiamos juntos.We always study together.
La misma forma sirve en cualquier contexto personal.The same form works in any personal context.	Rara vez llego temprano.I rarely arrive early.

Frequency adverbs specify the repetition of an action and allow expressing habits, customs, and exceptions with great precision. Their value depends both on the word chosen and on its position in the sentence, especially before the conjugated verb or the auxiliary, though variations exist depending on context and the variety of Spanish. Correct usage combines meaning, placement, and invariability, along with nuances such as reinforced negation and register preferences.