Käyttöikään

Käyttöikään is a Finnish term referring to the time span of a product's usable life. It is built from käyttö (use) and ikä (age) and is closely related to the noun käyttöikä, which denotes service life or expected lifespan. In Finnish technical and consumer texts, käyttöikään is used to express time-bound limits within which conditions apply. Typical phrases include käyttöikään saakka or käyttöikään asti, meaning until the end or for the duration of the service life. The concept is used in warranties, safety guidelines, and reliability assessments, where manufacturers or standards set a horizon for safe operation, maintenance needs, or replacement.

In practical terms, use of käyttöikään conveys that a device is designed to remain functional or compliant within its service life, subject to proper use and maintenance. Factors that influence the length of the service life include wear, fatigue, corrosion, operating conditions, and maintenance regimes. For labeling and standards, the service life is often estimated in years or operating hours and is sometimes accompanied by conditions that may shorten or extend it, such as environmental limits or duty cycles.

Etymology: the term combines käyttö (use) with ikä (age or lifetime) and is part of the family of words around durability and reliability in Finnish. See also käyttöikä, palveluikä, reliability engineering, product lifetime labeling.