おきに

The expression おきに attaches to a time expression to indicate a regular interval at which something happens. It means that the action occurs every X units of time, at intervals, or every other period. It is commonly used with days, weeks, or months (一日おきに, 三日おきに, 二週間おきに, 一か月おきに). The nuance is a scheduled repetition with a fixed spacing rather than a frequent occurrence. Often used to describe routines, maintenance, or periodic events.