Fixed frequency with flexible days
The useful distinction is between how often and when, and the two questions are often confused. An organisation may be entirely confident that two attendances a week is the right level of service while being genuinely unable to say which two days it will need in any given week. Separating those questions allows the frequency to be agreed and priced while the days remain adjustable within an agreed notice period.
That arrangement asks something of both sides and works only if both deliver. The organisation needs to nominate someone who will actually give the direction each week, and the cleaner needs to hold enough flexibility in the roster to accommodate it at short notice. Where either side cannot realistically commit to that, a fixed pattern with a sensible default is more honest and generally works better in practice.
