A baby needs to have its diaper changed often.
An example of often is how many times someone has to change the diaper of a baby each day.
Origin of oftenMiddle English variant, variety of oft
Origin of oftenMiddle English, alteration (probably influenced by selden, seldom) of oft, from Old English; see upo in Indo-European roots. Usage Note: The pronunciation of often with a (t) is a classic example of what is known as a spelling pronunciation. During the 1500s and 1600s, English experienced a widespread loss of certain consonant sounds within consonant clusters, as the (d) in handsome and handkerchief, the (p) in consumption and raspberry, and the (t) in chestnut and often. In this way the consonant clusters were simplified and made easier to articulate. But with the rise of public education and literacy in the 1800s, people became more aware of spelling, and sounds that had become silent were sometimes restored. This is the case with the (t) in often, which is acceptably pronounced with or without the (t). In similar words, such as soften and listen, the t has generally remained silent.
(comparative more often or oftener, superlative most often or oftenest)
From Old English oft, probably influenced by Middle English selden.