as often as not

Prepositional phrase

idiomatic

(idiomatic) More or less half of the time; on many occasions but not always; frequently.

Japanese Meaning

多くの場合、頻繁に（ただし必ずしも常にではなく、中には当てはまらない場合もある） / 概ね半分の時間、という傾向があるが例外もある

As often as not, the train is crowded during my commute.

通勤中、電車はだいたい半分くらいの時間混んでいます。

Sense（1）

(idiomatic) More or less half of the time; on many occasions but not always; frequently.