The three things a vague frequency hides
The first is who decides. If a task happens when required, someone must judge that the requirement exists, and a scope rarely says who. The second is the standard: required to reach what condition. The third is evidence, because a task that is only done sometimes leaves no trace of whether it was considered and skipped or never looked at. All three are solved by describing a check rather than a frequency.
A check reads differently from a task. Instead of clean the kitchen cupboard fronts as required, it reads cupboard fronts inspected every visit and cleaned where marked. The obligation is now to look, every time, which is verifiable and achievable. Whether the cloth touches the surface on a given evening becomes a matter of condition rather than a matter of dispute, and both parties are describing the same thing.
