Frequency words that are not frequencies
Regularly, periodically, as required and as needed all describe a rhythm without stating one. In practice they mean whatever the provider's schedule allows once the routine work is done, which is usually less than the buyer imagined when they read the word. Replace each with an interval: monthly, quarterly, twice yearly. An interval is checkable and a word like regularly is not and it removes the ambiguity entirely at no cost to either side.
The same applies to conditional wording. When required and where necessary place the judgement with whoever is holding the mop, which is not unreasonable for genuinely occasional tasks but is unhelpful for anything you expect to happen predictably. Decide which category each task belongs in and ask for the predictable ones to carry a stated interval in the document rather than leaving it to whoever is holding the mop that evening.
